diff --git a/composer.json b/composer.json
index 810351fed..9eb581475 100644
--- a/composer.json
+++ b/composer.json
@@ -14,7 +14,7 @@
         "guzzlehttp/promises": "^2.0",
         "guzzlehttp/psr7": "^2.0",
         "google/common-protos": "^4.4",
-        "google/longrunning": "~0.4",
+        "google/longrunning": "~0.4||^1.0",
         "ramsey/uuid": "^4.0"
     },
     "require-dev": {
diff --git a/dev/src/Docs/doctum-protobuf-config.php b/dev/src/Docs/doctum-protobuf-config.php
index e0efa81bd..6b98b37c9 100644
--- a/dev/src/Docs/doctum-protobuf-config.php
+++ b/dev/src/Docs/doctum-protobuf-config.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2022 Google LLC
  * All rights reserved.
diff --git a/src/AgentHeader.php b/src/AgentHeader.php
index 4fda2b0e9..4754a9752 100644
--- a/src/AgentHeader.php
+++ b/src/AgentHeader.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2016 Google LLC
  * All rights reserved.
@@ -124,7 +126,7 @@ public static function readGapicVersionFromFile(string $callingClass)
         $versionFile = substr(
             $callingClassFile,
             0,
-            strrpos($callingClassFile, DIRECTORY_SEPARATOR . 'src' . DIRECTORY_SEPARATOR)
+            strrpos($callingClassFile, DIRECTORY_SEPARATOR . 'src' . DIRECTORY_SEPARATOR) ?: 0
         ) . DIRECTORY_SEPARATOR . 'VERSION';
 
         return Version::readVersionFile($versionFile);
diff --git a/src/ServiceAddressTrait.php b/src/ApiEndpointTrait.php
similarity index 89%
rename from src/ServiceAddressTrait.php
rename to src/ApiEndpointTrait.php
index 1343a233c..df74fed5c 100644
--- a/src/ServiceAddressTrait.php
+++ b/src/ApiEndpointTrait.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2018 Google LLC
  * All rights reserved.
@@ -34,12 +36,8 @@
 
 /**
  * Provides helper methods for service address handling.
- *
- * @deprecated
- * @todo (dwsupplee) serviceAddress is deprecated now in favor of
- *        apiEndpoint. Rename the trait/method in our next major release.
  */
-trait ServiceAddressTrait
+trait ApiEndpointTrait
 {
     private static $defaultPort = 443;
 
@@ -48,7 +46,7 @@ trait ServiceAddressTrait
      * @return array
      * @throws ValidationException
      */
-    private static function normalizeServiceAddress(string $apiEndpoint)
+    private static function normalizeApiEndpoint(string $apiEndpoint)
     {
         $components = explode(':', $apiEndpoint);
         if (count($components) == 2) {
diff --git a/src/ApiException.php b/src/ApiException.php
index 89843149e..db1341f3f 100644
--- a/src/ApiException.php
+++ b/src/ApiException.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2016 Google LLC
  * All rights reserved.
diff --git a/src/ApiKeyHeaderCredentials.php b/src/ApiKeyHeaderCredentials.php
index f4471d6e9..9c84509ec 100644
--- a/src/ApiKeyHeaderCredentials.php
+++ b/src/ApiKeyHeaderCredentials.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2024 Google LLC
  * All rights reserved.
diff --git a/src/ApiStatus.php b/src/ApiStatus.php
index aa6adcfc1..b24a460a3 100644
--- a/src/ApiStatus.php
+++ b/src/ApiStatus.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2017 Google LLC
  * All rights reserved.
diff --git a/src/ArrayTrait.php b/src/ArrayTrait.php
index 02638be0c..2e57e10ea 100644
--- a/src/ArrayTrait.php
+++ b/src/ArrayTrait.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2018 Google LLC
  * All rights reserved.
diff --git a/src/BidiStream.php b/src/BidiStream.php
index e4d6718b2..29304decd 100644
--- a/src/BidiStream.php
+++ b/src/BidiStream.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2016 Google LLC
  * All rights reserved.
diff --git a/src/Call.php b/src/Call.php
index 53c5d32bb..a3ac9f05b 100644
--- a/src/Call.php
+++ b/src/Call.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2018 Google LLC
  * All rights reserved.
diff --git a/src/ClientOptionsTrait.php b/src/ClientOptionsTrait.php
index 5def36e9e..9b113c022 100644
--- a/src/ClientOptionsTrait.php
+++ b/src/ClientOptionsTrait.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2024 Google LLC
  * All rights reserved.
diff --git a/src/ClientStream.php b/src/ClientStream.php
index 6c249551c..a7622e5c8 100644
--- a/src/ClientStream.php
+++ b/src/ClientStream.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2016 Google LLC
  * All rights reserved.
diff --git a/src/CredentialsWrapper.php b/src/CredentialsWrapper.php
index d6e90892b..d80fc0863 100644
--- a/src/CredentialsWrapper.php
+++ b/src/CredentialsWrapper.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2018 Google LLC
  * All rights reserved.
@@ -214,24 +216,6 @@ public function getProjectId(?callable $httpHandler = null): ?string
         return null;
     }
 
-    /**
-     * @deprecated
-     * @return string Bearer string containing access token.
-     */
-    public function getBearerString()
-    {
-        $token = $this->credentialsFetcher->getLastReceivedToken();
-        if (self::isExpired($token)) {
-            $this->checkUniverseDomain();
-
-            $token = $this->credentialsFetcher->fetchAuthToken($this->authHttpHandler);
-            if (!self::isValid($token)) {
-                return '';
-            }
-        }
-        return empty($token['access_token']) ? '' : 'Bearer ' . $token['access_token'];
-    }
-
     /**
      * @param string $audience optional audience for self-signed JWTs.
      * @return callable Callable function that returns an authorization header.
diff --git a/src/FixedSizeCollection.php b/src/FixedSizeCollection.php
index 03ec835c1..13d4f3219 100644
--- a/src/FixedSizeCollection.php
+++ b/src/FixedSizeCollection.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2016 Google LLC
  * All rights reserved.
diff --git a/src/GPBLabel.php b/src/GPBLabel.php
index 18208cd64..23ae4ed3e 100644
--- a/src/GPBLabel.php
+++ b/src/GPBLabel.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2017 Google LLC
  * All rights reserved.
diff --git a/src/GPBType.php b/src/GPBType.php
index e6f50fa93..40bd90d72 100644
--- a/src/GPBType.php
+++ b/src/GPBType.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2017 Google LLC
  * All rights reserved.
diff --git a/src/GapicClientTrait.php b/src/GapicClientTrait.php
index 7a527ee32..1dbdad222 100644
--- a/src/GapicClientTrait.php
+++ b/src/GapicClientTrait.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2018 Google LLC
  * All rights reserved.
@@ -32,7 +34,6 @@
 
 namespace Google\ApiCore;
 
-use Google\ApiCore\LongRunning\OperationsClient;
 use Google\ApiCore\Middleware\CredentialsWrapperMiddleware;
 use Google\ApiCore\Middleware\FixedHeaderMiddleware;
 use Google\ApiCore\Middleware\OperationsMiddleware;
@@ -50,6 +51,7 @@
 use Google\ApiCore\Transport\TransportInterface;
 use Google\Auth\FetchAuthTokenInterface;
 use Google\LongRunning\Operation;
+use Google\LongRunning\OperationsClient;
 use Google\Protobuf\Internal\Message;
 use GuzzleHttp\Promise\PromiseInterface;
 
diff --git a/src/GrpcSupportTrait.php b/src/GrpcSupportTrait.php
index 85251eeee..a9418b70c 100644
--- a/src/GrpcSupportTrait.php
+++ b/src/GrpcSupportTrait.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2018 Google LLC
  * All rights reserved.
diff --git a/src/HeaderCredentialsInterface.php b/src/HeaderCredentialsInterface.php
index 805f61e6b..c4a4032db 100644
--- a/src/HeaderCredentialsInterface.php
+++ b/src/HeaderCredentialsInterface.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2024 Google LLC
  * All rights reserved.
diff --git a/src/InsecureCredentialsWrapper.php b/src/InsecureCredentialsWrapper.php
index 58b3ab578..f6ef9b5c4 100644
--- a/src/InsecureCredentialsWrapper.php
+++ b/src/InsecureCredentialsWrapper.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2024 Google LLC
  * All rights reserved.
diff --git a/src/InsecureRequestBuilder.php b/src/InsecureRequestBuilder.php
index 6b6da3d13..914570248 100644
--- a/src/InsecureRequestBuilder.php
+++ b/src/InsecureRequestBuilder.php
@@ -1,4 +1,5 @@
 <?php
+declare(strict_types=1);
 
 namespace Google\ApiCore;
 
diff --git a/src/KnownTypes.php b/src/KnownTypes.php
index 8d55402d4..f047e0107 100644
--- a/src/KnownTypes.php
+++ b/src/KnownTypes.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2025 Google LLC
  * All rights reserved.
@@ -38,11 +40,6 @@ class KnownTypes
 {
     private static bool $initialized = false;
 
-    /** @deprecated use BIN_TYPES instead */
-    public const GRPC_TYPES = self::BIN_TYPES;
-    /** @deprecated use TYPE_URLS instead */
-    public const JSON_TYPES = self::TYPE_URLS;
-
     public const BIN_TYPES = [
         'google.rpc.retryinfo-bin' => \Google\Rpc\RetryInfo::class,
         'google.rpc.debuginfo-bin' => \Google\Rpc\DebugInfo::class,
diff --git a/src/Middleware/CredentialsWrapperMiddleware.php b/src/Middleware/CredentialsWrapperMiddleware.php
index 086df0ef0..e406e7766 100644
--- a/src/Middleware/CredentialsWrapperMiddleware.php
+++ b/src/Middleware/CredentialsWrapperMiddleware.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2018 Google LLC
  * All rights reserved.
diff --git a/src/Middleware/FixedHeaderMiddleware.php b/src/Middleware/FixedHeaderMiddleware.php
index f3204b548..89eb1c782 100644
--- a/src/Middleware/FixedHeaderMiddleware.php
+++ b/src/Middleware/FixedHeaderMiddleware.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2018 Google LLC
  * All rights reserved.
diff --git a/src/Middleware/MiddlewareInterface.php b/src/Middleware/MiddlewareInterface.php
index 224006ffe..c73ee3fd8 100644
--- a/src/Middleware/MiddlewareInterface.php
+++ b/src/Middleware/MiddlewareInterface.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2023 Google LLC
  * All rights reserved.
diff --git a/src/Middleware/OperationsMiddleware.php b/src/Middleware/OperationsMiddleware.php
index e7f9baca6..bfbb691a7 100644
--- a/src/Middleware/OperationsMiddleware.php
+++ b/src/Middleware/OperationsMiddleware.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2018 Google LLC
  * All rights reserved.
diff --git a/src/Middleware/OptionsFilterMiddleware.php b/src/Middleware/OptionsFilterMiddleware.php
index d5027fe4b..7359c692e 100644
--- a/src/Middleware/OptionsFilterMiddleware.php
+++ b/src/Middleware/OptionsFilterMiddleware.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2018 Google LLC
  * All rights reserved.
diff --git a/src/Middleware/PagedMiddleware.php b/src/Middleware/PagedMiddleware.php
index b396281e9..9162a505f 100644
--- a/src/Middleware/PagedMiddleware.php
+++ b/src/Middleware/PagedMiddleware.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2018 Google LLC
  * All rights reserved.
diff --git a/src/Middleware/RequestAutoPopulationMiddleware.php b/src/Middleware/RequestAutoPopulationMiddleware.php
index 4811664ea..36a9386ed 100644
--- a/src/Middleware/RequestAutoPopulationMiddleware.php
+++ b/src/Middleware/RequestAutoPopulationMiddleware.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2024 Google LLC
  * All rights reserved.
diff --git a/src/Middleware/ResponseMetadataMiddleware.php b/src/Middleware/ResponseMetadataMiddleware.php
index c9dbdef21..31bb8454e 100644
--- a/src/Middleware/ResponseMetadataMiddleware.php
+++ b/src/Middleware/ResponseMetadataMiddleware.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2018 Google LLC
  * All rights reserved.
diff --git a/src/Middleware/RetryMiddleware.php b/src/Middleware/RetryMiddleware.php
index a86e120d6..eeb1aad7d 100644
--- a/src/Middleware/RetryMiddleware.php
+++ b/src/Middleware/RetryMiddleware.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2018 Google LLC
  * All rights reserved.
diff --git a/src/Middleware/TransportCallMiddleware.php b/src/Middleware/TransportCallMiddleware.php
index 1306f78e1..dfd68cc12 100644
--- a/src/Middleware/TransportCallMiddleware.php
+++ b/src/Middleware/TransportCallMiddleware.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2025 Google LLC
  * All rights reserved.
diff --git a/src/OperationResponse.php b/src/OperationResponse.php
index 8e58c810e..2652a968a 100644
--- a/src/OperationResponse.php
+++ b/src/OperationResponse.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2016 Google LLC
  * All rights reserved.
diff --git a/src/Options/CallOptions.php b/src/Options/CallOptions.php
index bae69ddd0..8a2cb44d3 100644
--- a/src/Options/CallOptions.php
+++ b/src/Options/CallOptions.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2023 Google LLC
  * All rights reserved.
@@ -136,16 +138,6 @@ public function setTransportOptions(array $transportOptions): self
         return $this;
     }
 
-    /**
-     * @deprecated use CallOptions::setTransportOptions
-     */
-    public function setTransportSpecificOptions(array $transportSpecificOptions): self
-    {
-        $this->setTransportOptions($transportSpecificOptions);
-
-        return $this;
-    }
-
     /**
      * @param RetrySettings|array|null $retrySettings
      *
diff --git a/src/Options/ClientOptions.php b/src/Options/ClientOptions.php
index b9677fe20..994bbc81b 100644
--- a/src/Options/ClientOptions.php
+++ b/src/Options/ClientOptions.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2023 Google LLC
  * All rights reserved.
diff --git a/src/Options/OptionsInterface.php b/src/Options/OptionsInterface.php
index 684d27e65..910b27ae8 100644
--- a/src/Options/OptionsInterface.php
+++ b/src/Options/OptionsInterface.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2025 Google LLC
  * All rights reserved.
diff --git a/src/Options/OptionsTrait.php b/src/Options/OptionsTrait.php
index 64ca7cb6b..444027c66 100644
--- a/src/Options/OptionsTrait.php
+++ b/src/Options/OptionsTrait.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2023 Google LLC
  * All rights reserved.
diff --git a/src/Options/TransportOptions.php b/src/Options/TransportOptions.php
index 3334d6f6c..af8fa3994 100644
--- a/src/Options/TransportOptions.php
+++ b/src/Options/TransportOptions.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2023 Google LLC
  * All rights reserved.
diff --git a/src/Options/TransportOptions/GrpcFallbackTransportOptions.php b/src/Options/TransportOptions/GrpcFallbackTransportOptions.php
index 9f94b235e..c5ad5ea40 100644
--- a/src/Options/TransportOptions/GrpcFallbackTransportOptions.php
+++ b/src/Options/TransportOptions/GrpcFallbackTransportOptions.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2023 Google LLC
  * All rights reserved.
diff --git a/src/Options/TransportOptions/GrpcTransportOptions.php b/src/Options/TransportOptions/GrpcTransportOptions.php
index 051b57bbe..5708cf085 100644
--- a/src/Options/TransportOptions/GrpcTransportOptions.php
+++ b/src/Options/TransportOptions/GrpcTransportOptions.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2023 Google LLC
  * All rights reserved.
@@ -36,7 +38,6 @@
 use Closure;
 use Google\ApiCore\Options\OptionsInterface;
 use Google\ApiCore\Options\OptionsTrait;
-use Google\ApiCore\Transport\Grpc\UnaryInterceptorInterface;
 use Grpc\Channel;
 use Grpc\Interceptor;
 use Psr\Log\LoggerInterface;
@@ -56,7 +57,7 @@ class GrpcTransportOptions implements ArrayAccess, OptionsInterface
     private null|false|LoggerInterface $logger;
 
     /**
-     * @var Interceptor[]|UnaryInterceptorInterface[]
+     * @var Interceptor[]
      */
     private array $interceptors;
 
@@ -69,14 +70,8 @@ class GrpcTransportOptions implements ArrayAccess, OptionsInterface
      *    @type array $stubOpts Options used to construct the gRPC stub (see
      *          {@link https://grpc.github.io/grpc/core/group__grpc__arg__keys.html}).
      *    @type Channel $channel Grpc channel to be used.
-     *    @type Interceptor[]|UnaryInterceptorInterface[] $interceptors *EXPERIMENTAL*
+     *    @type Interceptor[] $interceptors *EXPERIMENTAL*
      *          Interceptors used to intercept RPC invocations before a call starts.
-     *          Please note that implementations of
-     *          {@see \Google\ApiCore\Transport\Grpc\UnaryInterceptorInterface} are
-     *          considered deprecated and support will be removed in a future
-     *          release. To prepare for this, please take the time to convert
-     *          `UnaryInterceptorInterface` implementations over to a class which
-     *          extends {@see Grpc\Interceptor}.
      *    @type callable $clientCertSource A callable which returns the client cert as a string.
      *    @type null|false|LoggerInterface A PSR-3 Logger Interface.
      * }
@@ -125,7 +120,7 @@ public function setChannel(?Channel $channel): self
     }
 
     /**
-     * @param Interceptor[]|UnaryInterceptorInterface[] $interceptors
+     * @param Interceptor[] $interceptors
      *
      * @return $this
      */
diff --git a/src/Options/TransportOptions/RestTransportOptions.php b/src/Options/TransportOptions/RestTransportOptions.php
index ea55e2e97..53b6f3c89 100644
--- a/src/Options/TransportOptions/RestTransportOptions.php
+++ b/src/Options/TransportOptions/RestTransportOptions.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2023 Google LLC
  * All rights reserved.
diff --git a/src/Page.php b/src/Page.php
index 996cadf39..8609faccd 100644
--- a/src/Page.php
+++ b/src/Page.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2016 Google LLC
  * All rights reserved.
diff --git a/src/PageStreamingDescriptor.php b/src/PageStreamingDescriptor.php
index 351eaf7fc..f68b7372e 100644
--- a/src/PageStreamingDescriptor.php
+++ b/src/PageStreamingDescriptor.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2016 Google LLC
  * All rights reserved.
diff --git a/src/PagedListResponse.php b/src/PagedListResponse.php
index 62e6511ee..d9229a869 100644
--- a/src/PagedListResponse.php
+++ b/src/PagedListResponse.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2016 Google LLC
  * All rights reserved.
diff --git a/src/PathTemplate.php b/src/PathTemplate.php
index 4556acf07..953185aed 100644
--- a/src/PathTemplate.php
+++ b/src/PathTemplate.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2016 Google LLC
  * All rights reserved.
diff --git a/src/PollingTrait.php b/src/PollingTrait.php
index 526b01255..de5a99dac 100644
--- a/src/PollingTrait.php
+++ b/src/PollingTrait.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2018 Google LLC
  * All rights reserved.
@@ -64,7 +66,7 @@ private function poll(callable $pollCallable, array $options)
             if ($hasTotalPollTimeout && $this->getCurrentTimeMillis() > $endTime) {
                 return false;
             }
-            $this->sleepMillis($currentPollDelayMillis);
+            $this->sleepMillis((int) $currentPollDelayMillis);
             if ($pollCallable()) {
                 return true;
             }
diff --git a/src/RequestBuilder.php b/src/RequestBuilder.php
index b0d589dc4..246991c1f 100644
--- a/src/RequestBuilder.php
+++ b/src/RequestBuilder.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2018 Google LLC
  * All rights reserved.
diff --git a/src/RequestParamsHeaderDescriptor.php b/src/RequestParamsHeaderDescriptor.php
index 73e9af331..fca3c5426 100644
--- a/src/RequestParamsHeaderDescriptor.php
+++ b/src/RequestParamsHeaderDescriptor.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2017 Google LLC
  * All rights reserved.
diff --git a/src/ResourceHelperTrait.php b/src/ResourceHelperTrait.php
index 7f168413b..58c85423d 100644
--- a/src/ResourceHelperTrait.php
+++ b/src/ResourceHelperTrait.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2022 Google LLC
  * All rights reserved.
diff --git a/src/ResourceTemplate/AbsoluteResourceTemplate.php b/src/ResourceTemplate/AbsoluteResourceTemplate.php
index e6cb49231..8f25ba891 100644
--- a/src/ResourceTemplate/AbsoluteResourceTemplate.php
+++ b/src/ResourceTemplate/AbsoluteResourceTemplate.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2018 Google LLC
  * All rights reserved.
diff --git a/src/ResourceTemplate/Parser.php b/src/ResourceTemplate/Parser.php
index 2bc70ad33..7d916ede4 100644
--- a/src/ResourceTemplate/Parser.php
+++ b/src/ResourceTemplate/Parser.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2018 Google LLC
  * All rights reserved.
diff --git a/src/ResourceTemplate/RelativeResourceTemplate.php b/src/ResourceTemplate/RelativeResourceTemplate.php
index 941508807..5f378469e 100644
--- a/src/ResourceTemplate/RelativeResourceTemplate.php
+++ b/src/ResourceTemplate/RelativeResourceTemplate.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2018 Google LLC
  * All rights reserved.
@@ -115,10 +117,10 @@ public function render(array $bindings)
                 throw $this->renderingException($bindings, "missing required binding '$key' for segment '$segment'");
             }
             $value = $bindings[$key];
-            if (!is_null($value) && $segment->matches($value)) {
+            if (!is_null($value) && $segment->matches((string) $value)) {
                 $literalSegments[] = new Segment(
                     Segment::LITERAL_SEGMENT,
-                    $value,
+                    (string) $value,
                     $segment->getValue(),
                     $segment->getTemplate(),
                     $segment->getSeparator()
diff --git a/src/ResourceTemplate/ResourceTemplateInterface.php b/src/ResourceTemplate/ResourceTemplateInterface.php
index ffa3c8138..d5cb1357f 100644
--- a/src/ResourceTemplate/ResourceTemplateInterface.php
+++ b/src/ResourceTemplate/ResourceTemplateInterface.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2018 Google LLC
  * All rights reserved.
diff --git a/src/ResourceTemplate/Segment.php b/src/ResourceTemplate/Segment.php
index fb9dc6d43..a54a107c5 100644
--- a/src/ResourceTemplate/Segment.php
+++ b/src/ResourceTemplate/Segment.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2018 Google LLC
  * All rights reserved.
diff --git a/src/RetrySettings.php b/src/RetrySettings.php
index 018b5066d..c376155d3 100644
--- a/src/RetrySettings.php
+++ b/src/RetrySettings.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2016 Google LLC
  * All rights reserved.
diff --git a/src/Serializer.php b/src/Serializer.php
index b68892226..c0278e7c9 100644
--- a/src/Serializer.php
+++ b/src/Serializer.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2017 Google LLC
  * All rights reserved.
@@ -209,7 +211,7 @@ public static function decodeMetadata(array $metadata, ?array &$errors = null)
         foreach ($metadata as $key => $values) {
             foreach ($values as $value) {
                 $decodedValue = ['@type' => $key];
-                if (self::hasBinaryHeaderSuffix($key)) {
+                if (is_string($key) && self::hasBinaryHeaderSuffix($key)) {
                     if (isset(KnownTypes::BIN_TYPES[$key])) {
                         $class = KnownTypes::BIN_TYPES[$key];
                         /** @var Message $message */
diff --git a/src/ServerStream.php b/src/ServerStream.php
index 3257e6550..c659041c5 100644
--- a/src/ServerStream.php
+++ b/src/ServerStream.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2016 Google LLC
  * All rights reserved.
diff --git a/src/ServerStreamingCallInterface.php b/src/ServerStreamingCallInterface.php
index a78ff275e..ae8cc3ed5 100644
--- a/src/ServerStreamingCallInterface.php
+++ b/src/ServerStreamingCallInterface.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2021 Google LLC
  * All rights reserved.
diff --git a/src/Testing/GeneratedTest.php b/src/Testing/GeneratedTest.php
index f8d4c1af4..41fe7d328 100644
--- a/src/Testing/GeneratedTest.php
+++ b/src/Testing/GeneratedTest.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2017 Google LLC
  * All rights reserved.
diff --git a/src/Testing/MessageAwareArrayComparator.php b/src/Testing/MessageAwareArrayComparator.php
index 9feedb0ef..05287b954 100644
--- a/src/Testing/MessageAwareArrayComparator.php
+++ b/src/Testing/MessageAwareArrayComparator.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /**
  * Copyright 2018 Google LLC
  *
diff --git a/src/Testing/MessageAwareExporter.php b/src/Testing/MessageAwareExporter.php
index 2aeb29cb0..5f7711b5c 100644
--- a/src/Testing/MessageAwareExporter.php
+++ b/src/Testing/MessageAwareExporter.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /**
  * Copyright 2018 Google LLC
  *
diff --git a/src/Testing/MockBidiStreamingCall.php b/src/Testing/MockBidiStreamingCall.php
index 815cef8fc..359840eda 100644
--- a/src/Testing/MockBidiStreamingCall.php
+++ b/src/Testing/MockBidiStreamingCall.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2016 Google LLC
  * All rights reserved.
diff --git a/src/Testing/MockClientStreamingCall.php b/src/Testing/MockClientStreamingCall.php
index ca28e3dbf..3abfd2247 100644
--- a/src/Testing/MockClientStreamingCall.php
+++ b/src/Testing/MockClientStreamingCall.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2016 Google LLC
  * All rights reserved.
diff --git a/src/Testing/MockGrpcTransport.php b/src/Testing/MockGrpcTransport.php
index d6af2fe4f..851f48c4e 100644
--- a/src/Testing/MockGrpcTransport.php
+++ b/src/Testing/MockGrpcTransport.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2018 Google LLC
  * All rights reserved.
diff --git a/src/Testing/MockServerStreamingCall.php b/src/Testing/MockServerStreamingCall.php
index d0dcead5d..f3ab92a0e 100644
--- a/src/Testing/MockServerStreamingCall.php
+++ b/src/Testing/MockServerStreamingCall.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2016 Google LLC
  * All rights reserved.
diff --git a/src/Testing/MockStatus.php b/src/Testing/MockStatus.php
index 6f2906356..78354bc0b 100644
--- a/src/Testing/MockStatus.php
+++ b/src/Testing/MockStatus.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2016 Google LLC
  * All rights reserved.
diff --git a/src/Testing/MockStubTrait.php b/src/Testing/MockStubTrait.php
index db69910aa..182d14df8 100644
--- a/src/Testing/MockStubTrait.php
+++ b/src/Testing/MockStubTrait.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2016 Google LLC
  * All rights reserved.
diff --git a/src/Testing/MockTransport.php b/src/Testing/MockTransport.php
index 333cb0b51..524280ac4 100644
--- a/src/Testing/MockTransport.php
+++ b/src/Testing/MockTransport.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2018 Google LLC
  * All rights reserved.
diff --git a/src/Testing/MockUnaryCall.php b/src/Testing/MockUnaryCall.php
index 431b041bf..1009df53f 100644
--- a/src/Testing/MockUnaryCall.php
+++ b/src/Testing/MockUnaryCall.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2016 Google LLC
  * All rights reserved.
diff --git a/src/Testing/ProtobufGPBEmptyComparator.php b/src/Testing/ProtobufGPBEmptyComparator.php
index b6871a8e4..5c639c4db 100644
--- a/src/Testing/ProtobufGPBEmptyComparator.php
+++ b/src/Testing/ProtobufGPBEmptyComparator.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /**
  * Copyright 2018 Google LLC
  *
diff --git a/src/Testing/ProtobufMessageComparator.php b/src/Testing/ProtobufMessageComparator.php
index 55fb21367..fac9ee852 100644
--- a/src/Testing/ProtobufMessageComparator.php
+++ b/src/Testing/ProtobufMessageComparator.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /**
  * Copyright 2018 Google LLC
  *
diff --git a/src/Testing/ReceivedRequest.php b/src/Testing/ReceivedRequest.php
index 97cc1d271..0d69e2c0c 100644
--- a/src/Testing/ReceivedRequest.php
+++ b/src/Testing/ReceivedRequest.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2016 Google LLC
  * All rights reserved.
diff --git a/src/Testing/SerializationTrait.php b/src/Testing/SerializationTrait.php
index c703f0dea..c80c6938a 100644
--- a/src/Testing/SerializationTrait.php
+++ b/src/Testing/SerializationTrait.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2017 Google LLC
  * All rights reserved.
diff --git a/src/Transport/Grpc/ForwardingCall.php b/src/Transport/Grpc/ForwardingCall.php
index 2ec4f73fc..12e4a092f 100644
--- a/src/Transport/Grpc/ForwardingCall.php
+++ b/src/Transport/Grpc/ForwardingCall.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2018 Google LLC
  * All rights reserved.
diff --git a/src/Transport/Grpc/ForwardingServerStreamingCall.php b/src/Transport/Grpc/ForwardingServerStreamingCall.php
index 10e4ee706..efaeb5b8c 100644
--- a/src/Transport/Grpc/ForwardingServerStreamingCall.php
+++ b/src/Transport/Grpc/ForwardingServerStreamingCall.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2020 Google LLC
  * All rights reserved.
diff --git a/src/Transport/Grpc/ForwardingUnaryCall.php b/src/Transport/Grpc/ForwardingUnaryCall.php
index 81b00646d..eb1c95116 100644
--- a/src/Transport/Grpc/ForwardingUnaryCall.php
+++ b/src/Transport/Grpc/ForwardingUnaryCall.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2018 Google LLC
  * All rights reserved.
diff --git a/src/Transport/Grpc/ServerStreamingCallWrapper.php b/src/Transport/Grpc/ServerStreamingCallWrapper.php
index bdf49d624..785d13f3d 100644
--- a/src/Transport/Grpc/ServerStreamingCallWrapper.php
+++ b/src/Transport/Grpc/ServerStreamingCallWrapper.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2021 Google LLC
  * All rights reserved.
diff --git a/src/Transport/Grpc/UnaryInterceptorInterface.php b/src/Transport/Grpc/UnaryInterceptorInterface.php
deleted file mode 100644
index fa510ea39..000000000
--- a/src/Transport/Grpc/UnaryInterceptorInterface.php
+++ /dev/null
@@ -1,61 +0,0 @@
-<?php
-/*
- * Copyright 2018 Google LLC
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
- *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
-
-namespace Google\ApiCore\Transport\Grpc;
-
-/**
- * Temporary class to support an interceptor-like interface until gRPC interceptor support is
- * available.
- *
- * @experimental
- * @deprecated Deprecated in favor of implementations extending {@see \Grpc\Interceptor}.
- */
-interface UnaryInterceptorInterface
-{
-    /**
-     * @param string $method
-     * @param \Google\Protobuf\Internal\Message $argument
-     * @param callable $deserialize
-     * @param array $metadata
-     * @param array $options
-     * @param callable $continuation
-     * @return mixed
-     */
-    public function interceptUnaryUnary(
-        $method,
-        $argument,
-        $deserialize,
-        array $metadata,
-        array $options,
-        callable $continuation
-    );
-}
diff --git a/src/Transport/GrpcFallbackTransport.php b/src/Transport/GrpcFallbackTransport.php
index b248b052e..f43376a81 100644
--- a/src/Transport/GrpcFallbackTransport.php
+++ b/src/Transport/GrpcFallbackTransport.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2018 Google LLC
  * All rights reserved.
@@ -31,10 +33,10 @@
  */
 namespace Google\ApiCore\Transport;
 
+use Google\ApiCore\ApiEndpointTrait;
 use Google\ApiCore\ApiException;
 use Google\ApiCore\ApiStatus;
 use Google\ApiCore\Call;
-use Google\ApiCore\ServiceAddressTrait;
 use Google\ApiCore\ValidationException;
 use Google\ApiCore\ValidationTrait;
 use Google\Protobuf\Internal\Message;
@@ -50,8 +52,8 @@
  */
 class GrpcFallbackTransport implements TransportInterface
 {
+    use ApiEndpointTrait;
     use ValidationTrait;
-    use ServiceAddressTrait;
     use HttpUnaryTransportTrait;
 
     private string $baseUri;
@@ -89,7 +91,7 @@ public static function build(string $apiEndpoint, array $config = [])
             'clientCertSource' => null,
             'logger' => null,
         ];
-        list($baseUri, $port) = self::normalizeServiceAddress($apiEndpoint);
+        list($baseUri, $port) = self::normalizeApiEndpoint($apiEndpoint);
         $httpHandler = $config['httpHandler'] ?: self::buildHttpHandlerAsync(logger: $config['logger']);
         $transport = new GrpcFallbackTransport("$baseUri:$port", $httpHandler);
         if ($config['clientCertSource']) {
diff --git a/src/Transport/GrpcTransport.php b/src/Transport/GrpcTransport.php
index 5fd03a6fe..188133546 100644
--- a/src/Transport/GrpcTransport.php
+++ b/src/Transport/GrpcTransport.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2018 Google LLC
  * All rights reserved.
@@ -33,15 +35,14 @@
 namespace Google\ApiCore\Transport;
 
 use Exception;
+use Google\ApiCore\ApiEndpointTrait;
 use Google\ApiCore\ApiException;
 use Google\ApiCore\BidiStream;
 use Google\ApiCore\Call;
 use Google\ApiCore\ClientStream;
 use Google\ApiCore\GrpcSupportTrait;
 use Google\ApiCore\ServerStream;
-use Google\ApiCore\ServiceAddressTrait;
 use Google\ApiCore\Transport\Grpc\ServerStreamingCallWrapper;
-use Google\ApiCore\Transport\Grpc\UnaryInterceptorInterface;
 use Google\ApiCore\ValidationException;
 use Google\ApiCore\ValidationTrait;
 use Google\Auth\Logging\LoggingTrait;
@@ -59,9 +60,9 @@
  */
 class GrpcTransport extends BaseStub implements TransportInterface
 {
+    use ApiEndpointTrait;
     use ValidationTrait;
     use GrpcSupportTrait;
-    use ServiceAddressTrait;
     use LoggingTrait;
 
     private null|LoggerInterface $logger;
@@ -73,14 +74,8 @@ class GrpcTransport extends BaseStub implements TransportInterface
      * metadata array, and returns an updated metadata array
      *  - 'grpc.primary_user_agent': (optional) a user-agent string
      * @param Channel $channel An already created Channel object (optional)
-     * @param Interceptor[]|UnaryInterceptorInterface[] $interceptors *EXPERIMENTAL*
+     * @param Interceptor[] $interceptors *EXPERIMENTAL*
      *        Interceptors used to intercept RPC invocations before a call starts.
-     *        Please note that implementations of
-     *        {@see \Google\ApiCore\Transport\Grpc\UnaryInterceptorInterface} are
-     *        considered deprecated and support will be removed in a future
-     *        release. To prepare for this, please take the time to convert
-     *        `UnaryInterceptorInterface` implementations over to a class which
-     *        extends {@see Grpc\Interceptor}.
      * @param null|false|LoggerInterface $logger A PSR-3 Compliant logger.
      * @throws Exception
      */
@@ -114,14 +109,8 @@ public function __construct(
      *    @type array $stubOpts Options used to construct the gRPC stub (see
      *          {@link https://grpc.github.io/grpc/core/group__grpc__arg__keys.html}).
      *    @type Channel $channel Grpc channel to be used.
-     *    @type Interceptor[]|UnaryInterceptorInterface[] $interceptors *EXPERIMENTAL*
+     *    @type Interceptor[] $interceptors *EXPERIMENTAL*
      *          Interceptors used to intercept RPC invocations before a call starts.
-     *          Please note that implementations of
-     *          {@see \Google\ApiCore\Transport\Grpc\UnaryInterceptorInterface} are
-     *          considered deprecated and support will be removed in a future
-     *          release. To prepare for this, please take the time to convert
-     *          `UnaryInterceptorInterface` implementations over to a class which
-     *          extends {@see Grpc\Interceptor}.
      *    @type callable $clientCertSource A callable which returns the client cert as a string.
      * }
      * @return GrpcTransport
@@ -137,7 +126,7 @@ public static function build(string $apiEndpoint, array $config = [])
             'clientCertSource' => null,
             'logger'           => null,
         ];
-        list($addr, $port) = self::normalizeServiceAddress($apiEndpoint);
+        list($addr, $port) = self::normalizeApiEndpoint($apiEndpoint);
         $host = "$addr:$port";
         $stubOpts = $config['stubOpts'];
         // Set the required 'credentials' key in stubOpts if it is not already set. Use
diff --git a/src/Transport/HttpUnaryTransportTrait.php b/src/Transport/HttpUnaryTransportTrait.php
index 38c4ca1f5..8a9b3bea1 100644
--- a/src/Transport/HttpUnaryTransportTrait.php
+++ b/src/Transport/HttpUnaryTransportTrait.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2018 Google LLC
  * All rights reserved.
diff --git a/src/Transport/Rest/JsonStreamDecoder.php b/src/Transport/Rest/JsonStreamDecoder.php
index c01f21135..3fab03d01 100644
--- a/src/Transport/Rest/JsonStreamDecoder.php
+++ b/src/Transport/Rest/JsonStreamDecoder.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2021 Google LLC
  * All rights reserved.
diff --git a/src/Transport/Rest/RestServerStreamingCall.php b/src/Transport/Rest/RestServerStreamingCall.php
index 35d796199..95fc5eae2 100644
--- a/src/Transport/Rest/RestServerStreamingCall.php
+++ b/src/Transport/Rest/RestServerStreamingCall.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2021 Google LLC
  * All rights reserved.
diff --git a/src/Transport/RestTransport.php b/src/Transport/RestTransport.php
index 296937fa4..99b8459c3 100644
--- a/src/Transport/RestTransport.php
+++ b/src/Transport/RestTransport.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2018 Google LLC
  * All rights reserved.
@@ -31,12 +33,12 @@
  */
 namespace Google\ApiCore\Transport;
 
+use Google\ApiCore\ApiEndpointTrait;
 use Google\ApiCore\ApiException;
 use Google\ApiCore\Call;
 use Google\ApiCore\InsecureRequestBuilder;
 use Google\ApiCore\RequestBuilder;
 use Google\ApiCore\ServerStream;
-use Google\ApiCore\ServiceAddressTrait;
 use Google\ApiCore\Transport\Rest\RestServerStreamingCall;
 use Google\ApiCore\ValidationException;
 use Google\ApiCore\ValidationTrait;
@@ -50,8 +52,8 @@
  */
 class RestTransport implements TransportInterface
 {
+    use ApiEndpointTrait;
     use ValidationTrait;
-    use ServiceAddressTrait;
     use HttpUnaryTransportTrait {
         startServerStreamingCall as protected unsupportedServerStreamingCall;
     }
@@ -97,7 +99,7 @@ public static function build(string $apiEndpoint, string $restConfigPath, array
             'hasEmulator' => false,
             'logger' => null,
         ];
-        list($baseUri, $port) = self::normalizeServiceAddress($apiEndpoint);
+        list($baseUri, $port) = self::normalizeApiEndpoint($apiEndpoint);
         $requestBuilder = $config['hasEmulator']
             ? new InsecureRequestBuilder("$baseUri:$port", $restConfigPath)
             : new RequestBuilder("$baseUri:$port", $restConfigPath);
diff --git a/src/Transport/TransportInterface.php b/src/Transport/TransportInterface.php
index 682a43019..8ae6d918c 100644
--- a/src/Transport/TransportInterface.php
+++ b/src/Transport/TransportInterface.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2018 Google LLC
  * All rights reserved.
diff --git a/src/UriTrait.php b/src/UriTrait.php
index d3fc6aa37..8b3b66722 100644
--- a/src/UriTrait.php
+++ b/src/UriTrait.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2018 Google LLC
  * All rights reserved.
diff --git a/src/ValidationException.php b/src/ValidationException.php
index 27a66a82c..07ccb77f6 100644
--- a/src/ValidationException.php
+++ b/src/ValidationException.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2016 Google LLC
  * All rights reserved.
diff --git a/src/ValidationTrait.php b/src/ValidationTrait.php
index 5e554e3fb..aa6a85e2e 100644
--- a/src/ValidationTrait.php
+++ b/src/ValidationTrait.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2017 Google LLC
  * All rights reserved.
diff --git a/src/Version.php b/src/Version.php
index f181dd874..76839d474 100644
--- a/src/Version.php
+++ b/src/Version.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2018 Google LLC
  * All rights reserved.
diff --git a/tests/Conformance/src/V1beta1/Client/ComplianceClient.php b/tests/Conformance/src/V1beta1/Client/ComplianceClient.php
index 913c3456e..1cea6bb07 100644
--- a/tests/Conformance/src/V1beta1/Client/ComplianceClient.php
+++ b/tests/Conformance/src/V1beta1/Client/ComplianceClient.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2025 Google LLC
  *
diff --git a/tests/Conformance/src/V1beta1/Client/EchoClient.php b/tests/Conformance/src/V1beta1/Client/EchoClient.php
index eab8a8bc2..9da8859db 100644
--- a/tests/Conformance/src/V1beta1/Client/EchoClient.php
+++ b/tests/Conformance/src/V1beta1/Client/EchoClient.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2025 Google LLC
  *
diff --git a/tests/Conformance/src/V1beta1/Client/IdentityClient.php b/tests/Conformance/src/V1beta1/Client/IdentityClient.php
index 01c047823..9983b527d 100644
--- a/tests/Conformance/src/V1beta1/Client/IdentityClient.php
+++ b/tests/Conformance/src/V1beta1/Client/IdentityClient.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2025 Google LLC
  *
diff --git a/tests/Conformance/src/V1beta1/Client/MessagingClient.php b/tests/Conformance/src/V1beta1/Client/MessagingClient.php
index 6acea6553..9e6e78588 100644
--- a/tests/Conformance/src/V1beta1/Client/MessagingClient.php
+++ b/tests/Conformance/src/V1beta1/Client/MessagingClient.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2025 Google LLC
  *
diff --git a/tests/Conformance/src/V1beta1/Client/SequenceServiceClient.php b/tests/Conformance/src/V1beta1/Client/SequenceServiceClient.php
index f5f8681d1..b371b6238 100644
--- a/tests/Conformance/src/V1beta1/Client/SequenceServiceClient.php
+++ b/tests/Conformance/src/V1beta1/Client/SequenceServiceClient.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2025 Google LLC
  *
diff --git a/tests/Conformance/src/V1beta1/Client/TestingClient.php b/tests/Conformance/src/V1beta1/Client/TestingClient.php
index 27f077841..023a6a09e 100644
--- a/tests/Conformance/src/V1beta1/Client/TestingClient.php
+++ b/tests/Conformance/src/V1beta1/Client/TestingClient.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2025 Google LLC
  *
diff --git a/tests/Conformance/src/V1beta1/resources/compliance_descriptor_config.php b/tests/Conformance/src/V1beta1/resources/compliance_descriptor_config.php
index e1e912610..62bace0a0 100644
--- a/tests/Conformance/src/V1beta1/resources/compliance_descriptor_config.php
+++ b/tests/Conformance/src/V1beta1/resources/compliance_descriptor_config.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2025 Google LLC
  *
diff --git a/tests/Conformance/src/V1beta1/resources/compliance_rest_client_config.php b/tests/Conformance/src/V1beta1/resources/compliance_rest_client_config.php
index ffdb057e8..f31647faf 100644
--- a/tests/Conformance/src/V1beta1/resources/compliance_rest_client_config.php
+++ b/tests/Conformance/src/V1beta1/resources/compliance_rest_client_config.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2025 Google LLC
  *
diff --git a/tests/Conformance/src/V1beta1/resources/echo_descriptor_config.php b/tests/Conformance/src/V1beta1/resources/echo_descriptor_config.php
index 63b503e5c..6b8be07a5 100644
--- a/tests/Conformance/src/V1beta1/resources/echo_descriptor_config.php
+++ b/tests/Conformance/src/V1beta1/resources/echo_descriptor_config.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2025 Google LLC
  *
diff --git a/tests/Conformance/src/V1beta1/resources/echo_rest_client_config.php b/tests/Conformance/src/V1beta1/resources/echo_rest_client_config.php
index f1a999b60..ea04e2008 100644
--- a/tests/Conformance/src/V1beta1/resources/echo_rest_client_config.php
+++ b/tests/Conformance/src/V1beta1/resources/echo_rest_client_config.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2025 Google LLC
  *
diff --git a/tests/Conformance/src/V1beta1/resources/identity_descriptor_config.php b/tests/Conformance/src/V1beta1/resources/identity_descriptor_config.php
index b544be013..cec87feb8 100644
--- a/tests/Conformance/src/V1beta1/resources/identity_descriptor_config.php
+++ b/tests/Conformance/src/V1beta1/resources/identity_descriptor_config.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2025 Google LLC
  *
diff --git a/tests/Conformance/src/V1beta1/resources/identity_rest_client_config.php b/tests/Conformance/src/V1beta1/resources/identity_rest_client_config.php
index f80afb6d0..5ec47fff4 100644
--- a/tests/Conformance/src/V1beta1/resources/identity_rest_client_config.php
+++ b/tests/Conformance/src/V1beta1/resources/identity_rest_client_config.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2025 Google LLC
  *
diff --git a/tests/Conformance/src/V1beta1/resources/messaging_descriptor_config.php b/tests/Conformance/src/V1beta1/resources/messaging_descriptor_config.php
index f29f84658..ea5979a28 100644
--- a/tests/Conformance/src/V1beta1/resources/messaging_descriptor_config.php
+++ b/tests/Conformance/src/V1beta1/resources/messaging_descriptor_config.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2025 Google LLC
  *
diff --git a/tests/Conformance/src/V1beta1/resources/messaging_rest_client_config.php b/tests/Conformance/src/V1beta1/resources/messaging_rest_client_config.php
index 4b080078c..86111cdf4 100644
--- a/tests/Conformance/src/V1beta1/resources/messaging_rest_client_config.php
+++ b/tests/Conformance/src/V1beta1/resources/messaging_rest_client_config.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2025 Google LLC
  *
diff --git a/tests/Conformance/src/V1beta1/resources/sequence_service_descriptor_config.php b/tests/Conformance/src/V1beta1/resources/sequence_service_descriptor_config.php
index 64096e0fe..146bca25b 100644
--- a/tests/Conformance/src/V1beta1/resources/sequence_service_descriptor_config.php
+++ b/tests/Conformance/src/V1beta1/resources/sequence_service_descriptor_config.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2025 Google LLC
  *
diff --git a/tests/Conformance/src/V1beta1/resources/sequence_service_rest_client_config.php b/tests/Conformance/src/V1beta1/resources/sequence_service_rest_client_config.php
index 51d8310bc..6b8b811ef 100644
--- a/tests/Conformance/src/V1beta1/resources/sequence_service_rest_client_config.php
+++ b/tests/Conformance/src/V1beta1/resources/sequence_service_rest_client_config.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2025 Google LLC
  *
diff --git a/tests/Conformance/src/V1beta1/resources/testing_descriptor_config.php b/tests/Conformance/src/V1beta1/resources/testing_descriptor_config.php
index 6f62206cb..b37f32bbc 100644
--- a/tests/Conformance/src/V1beta1/resources/testing_descriptor_config.php
+++ b/tests/Conformance/src/V1beta1/resources/testing_descriptor_config.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2025 Google LLC
  *
diff --git a/tests/Conformance/src/V1beta1/resources/testing_rest_client_config.php b/tests/Conformance/src/V1beta1/resources/testing_rest_client_config.php
index a0e0e150a..c5bc8daf8 100644
--- a/tests/Conformance/src/V1beta1/resources/testing_rest_client_config.php
+++ b/tests/Conformance/src/V1beta1/resources/testing_rest_client_config.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2025 Google LLC
  *
diff --git a/tests/Unit/ServiceAddressTraitTest.php b/tests/Unit/ApiEndpointTraitTest.php
similarity index 62%
rename from tests/Unit/ServiceAddressTraitTest.php
rename to tests/Unit/ApiEndpointTraitTest.php
index ba5cf81c7..046909d61 100644
--- a/tests/Unit/ServiceAddressTraitTest.php
+++ b/tests/Unit/ApiEndpointTraitTest.php
@@ -17,29 +17,25 @@
 
 namespace Google\ApiCore\Tests\Unit;
 
-use Google\ApiCore\ServiceAddressTrait;
+use Google\ApiCore\ApiEndpointTrait;
 use Google\ApiCore\ValidationException;
 use PHPUnit\Framework\TestCase;
 
-/**
- * @todo (dwsupplee) serviceAddress is deprecated now in favor of
- *        apiEndpoint. Rename the tests/variables in our next major release.
- */
-class ServiceAddressTraitTest extends TestCase
+class ApiEndpointTraitTest extends TestCase
 {
-    use ServiceAddressTrait;
+    use ApiEndpointTrait;
 
     /**
-     * @dataProvider normalizeServiceAddressData
+     * @dataProvider normalizeApiEndpointData
      */
-    public function testNormalizeServiceAddress($serviceAddressString, $expectedAddress, $expectedPort)
+    public function testNormalizeApiEndpoint($ApiEndpointString, $expectedAddress, $expectedPort)
     {
-        list($actualAddress, $actualPort) = self::normalizeServiceAddress($serviceAddressString);
+        list($actualAddress, $actualPort) = self::normalizeApiEndpoint($ApiEndpointString);
         $this->assertSame($expectedAddress, $actualAddress);
         $this->assertSame($expectedPort, $actualPort);
     }
 
-    public function normalizeServiceAddressData()
+    public function normalizeApiEndpointData()
     {
         return [
             ['simple.com:123', 'simple.com', '123'],
@@ -49,17 +45,17 @@ public function normalizeServiceAddressData()
     }
 
     /**
-     * @dataProvider normalizeServiceAddressInvalidData
+     * @dataProvider normalizeApiEndpointInvalidData
      */
-    public function testNormalizeServiceAddressInvalid($serviceAddressString)
+    public function testNormalizeApiEndpointInvalid($ApiEndpointString)
     {
         $this->expectException(ValidationException::class);
         $this->expectExceptionMessage('Invalid apiEndpoint');
 
-        self::normalizeServiceAddress($serviceAddressString);
+        self::normalizeApiEndpoint($ApiEndpointString);
     }
 
-    public function normalizeServiceAddressInvalidData()
+    public function normalizeApiEndpointInvalidData()
     {
         return [
             ['too.many:colons:123'],
diff --git a/tests/Unit/CredentialsWrapperTest.php b/tests/Unit/CredentialsWrapperTest.php
index ca58ceadf..3b6b28b40 100644
--- a/tests/Unit/CredentialsWrapperTest.php
+++ b/tests/Unit/CredentialsWrapperTest.php
@@ -218,39 +218,6 @@ public function testCheckUniverseDomainFails(?string $universeDomain, ?string $c
         $credentialsWrapper->getAuthorizationHeaderCallback()();
     }
 
-    /**
-     * Same test as above, but calls the deprecated CredentialsWrapper::getBearerString method
-     * instead of CredentialsWrapper::getAuthorizationHeaderCallback
-     * @dataProvider provideCheckUniverseDomainFails
-     */
-    public function testCheckUniverseDomainOnGetBearerStringFails(
-        ?string $universeDomain,
-        ?string $credentialsUniverse,
-        ?string $message = null
-    ) {
-        $this->expectException(ValidationException::class);
-        $this->expectExceptionMessage($message ?: sprintf(
-            'The configured universe domain (%s) does not match the credential universe domain (%s)',
-            is_null($universeDomain) ? GetUniverseDomainInterface::DEFAULT_UNIVERSE_DOMAIN : $universeDomain,
-            is_null($credentialsUniverse) ? GetUniverseDomainInterface::DEFAULT_UNIVERSE_DOMAIN : $credentialsUniverse,
-        ));
-        $fetcher = $this->prophesize(FetchAuthTokenInterface::class);
-        // When the $credentialsUniverse is null, the fetcher doesn't implement GetUniverseDomainInterface
-        if (!is_null($credentialsUniverse)) {
-            $fetcher->willImplement(GetUniverseDomainInterface::class);
-            $fetcher->getUniverseDomain()->willReturn($credentialsUniverse);
-        }
-        $fetcher->getLastReceivedToken()->willReturn(null);
-        // When $universeDomain is null, it means no $universeDomain argument was provided
-        if (is_null($universeDomain)) {
-            $credentialsWrapper = new CredentialsWrapper($fetcher->reveal());
-        } else {
-            $credentialsWrapper = new CredentialsWrapper($fetcher->reveal(), null, $universeDomain);
-        }
-        // Check getBearerString (deprecated)
-        $credentialsWrapper->getBearerString();
-    }
-
     public function provideCheckUniverseDomainFails()
     {
         return [
@@ -286,11 +253,6 @@ public function testCheckUniverseDomainPasses(?string $universeDomain, ?string $
             ['authorization' => ['Bearer abc']],
             $credentialsWrapper->getAuthorizationHeaderCallback()()
         );
-        // Check getBearerString (deprecated)
-        $this->assertEquals(
-            'Bearer abc',
-            $credentialsWrapper->getBearerString()
-        );
     }
 
     public function provideCheckUniverseDomainPasses()
@@ -316,67 +278,6 @@ public function testCheckUniverseDomainOnGceCredentialsDoesNotCheck()
         $credentialsWrapper->checkUniverseDomain();
     }
 
-    /**
-     * @dataProvider getBearerStringData
-     */
-    public function testGetBearerString($fetcher, $expectedBearerString)
-    {
-        $credentialsWrapper = new CredentialsWrapper($fetcher);
-        $bearerString = $credentialsWrapper->getBearerString();
-        $this->assertSame($expectedBearerString, $bearerString);
-    }
-
-    public function getBearerStringData()
-    {
-        $expiredFetcher = $this->prophesize(FetchAuthTokenInterface::class);
-        $expiredFetcher->getLastReceivedToken()
-            ->willReturn([
-                'access_token' => 123,
-                'expires_at' => time() - 1
-            ]);
-        $expiredFetcher->fetchAuthToken(Argument::any())
-            ->willReturn([
-                'access_token' => 456,
-                'expires_at' => time() + 1000
-            ]);
-        $eagerExpiredFetcher = $this->prophesize(FetchAuthTokenInterface::class);
-        $eagerExpiredFetcher->getLastReceivedToken()
-            ->willReturn([
-                'access_token' => 123,
-                'expires_at' => time() + 1
-            ]);
-        $eagerExpiredFetcher->fetchAuthToken(Argument::any())
-            ->willReturn([
-                'access_token' => 456,
-                'expires_at' => time() + 10 // within 10 second eager threshold
-            ]);
-        $unexpiredFetcher = $this->prophesize(FetchAuthTokenInterface::class);
-        $unexpiredFetcher->getLastReceivedToken()
-            ->willReturn([
-                'access_token' => 123,
-                'expires_at' => time() + 100,
-            ]);
-        $insecureFetcher = $this->prophesize(FetchAuthTokenInterface::class);
-        $insecureFetcher->getLastReceivedToken()->willReturn(null);
-        $insecureFetcher->fetchAuthToken(Argument::any())
-            ->willReturn([
-                'access_token' => '',
-            ]);
-        $nullFetcher = $this->prophesize(FetchAuthTokenInterface::class);
-        $nullFetcher->getLastReceivedToken()->willReturn(null);
-        $nullFetcher->fetchAuthToken(Argument::any())
-            ->willReturn([
-                'access_token' => null,
-            ]);
-        return [
-            [$expiredFetcher->reveal(), 'Bearer 456'],
-            [$eagerExpiredFetcher->reveal(), 'Bearer 456'],
-            [$unexpiredFetcher->reveal(), 'Bearer 123'],
-            [$insecureFetcher->reveal(), ''],
-            [$nullFetcher->reveal(), '']
-        ];
-    }
-
     /**
      * @dataProvider getAuthorizationHeaderCallbackData
      */
diff --git a/tests/Unit/Middleware/OperationsMiddlewareTest.php b/tests/Unit/Middleware/OperationsMiddlewareTest.php
index 7d7dac941..1c264ae76 100644
--- a/tests/Unit/Middleware/OperationsMiddlewareTest.php
+++ b/tests/Unit/Middleware/OperationsMiddlewareTest.php
@@ -33,9 +33,9 @@
 namespace Google\ApiCore\Tests\Unit\Middleware;
 
 use Google\ApiCore\Call;
-use Google\ApiCore\LongRunning\OperationsClient;
+use Google\LongRunning\Client\OperationsClient;
 use Google\ApiCore\Middleware\OperationsMiddleware;
-use Google\ApiCore\Testing\MockResponse;
+use Google\ApiCore\Testing\MockRequest;
 use GuzzleHttp\Promise\Promise;
 use PHPUnit\Framework\TestCase;
 use Prophecy\PhpUnit\ProphecyTrait;
@@ -50,11 +50,11 @@ public function testOperationNameMethodDescriptor()
         $operationsClient = $this->prophesize(OperationsClient::class);
 
         $descriptor = [
-            'operationNameMethod' => 'getNumber'
+            'operationNameMethod' => 'getPageToken'
         ];
         $handler = function (Call $call, $options) use (&$callCount) {
             return $promise = new Promise(function () use (&$promise) {
-                $response = new MockResponse(['number' => 123]);
+                $response = new MockRequest(['page_token' => 'abc']);
                 $promise->resolve($response);
             });
         };
@@ -64,6 +64,6 @@ public function testOperationNameMethodDescriptor()
             []
         )->wait();
 
-        $this->assertEquals(123, $response->getName());
+        $this->assertEquals('abc', $response->getName());
     }
 }
diff --git a/tests/Unit/testdata/src/GapicClientStub.php b/tests/Unit/testdata/src/GapicClientStub.php
index ce1eff153..d045f427d 100644
--- a/tests/Unit/testdata/src/GapicClientStub.php
+++ b/tests/Unit/testdata/src/GapicClientStub.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /*
  * Copyright 2018 Google LLC
  * All rights reserved.