diff --git a/.evergreen/config.yml b/.evergreen/config.yml
index cff844729..f352e9495 100644
--- a/.evergreen/config.yml
+++ b/.evergreen/config.yml
@@ -148,7 +148,7 @@ functions:
   "upload test results":
     - command: attach.xunit_results
       params:
-        file: ./src/*/build/test-results/TEST-*.xml
+        file: ./src/tmp/rspec.xml
 
   "run tests":
     - command: shell.exec
@@ -249,10 +249,15 @@ axes:
     display_name: OS
     values:
       - id: debian
-        display_name: "Debian 11"
-        run_on: debian11-small
+        display_name: "Debian 12"
+        run_on: debian12-small
         variables:
-          MACHINE: "debian11"
+          MACHINE: "debian12"
+      - id: "ubuntu2404"
+        display_name: "Ubuntu 24.04"
+        run_on: ubuntu2404-small
+        variables:
+          MACHINE: "ubuntu2204"
       - id: "ubuntu2204"
         display_name: "Ubuntu 22.04"
         run_on: ubuntu2204-small
@@ -267,11 +272,11 @@ axes:
   - id: "special-os"
     display_name: OS
     values:
-      - id: "ubuntu2204-arm64"
-        display_name: "Ubuntu 22.04 ARM64"
-        run_on: ubuntu2204-arm64-small
+      - id: "ubuntu2404-arm64"
+        display_name: "Ubuntu 24.04 ARM64"
+        run_on: ubuntu2404-arm64-small
         variables:
-          MACHINE: ubuntu2204-arm64
+          MACHINE: ubuntu2404-arm64
 
   - id: ruby
     display_name: Ruby Version
@@ -296,6 +301,10 @@ axes:
         display_name: ruby-2.7
         variables:
            RVM_RUBY: ruby-2.7
+      - id: jruby-10.0
+        display_name: jruby-10.0
+        variables:
+           RVM_RUBY: jruby-10.0
       - id: jruby-9.4
         display_name: jruby-9.4
         variables:
@@ -390,13 +399,13 @@ buildvariants:
       - name: "test"
 
   - matrix_name: "special-os"
-    matrix_spec: { ruby: ["ruby-3.2", "ruby-3.1", "jruby-9.4"], special-os: '*' }
+    matrix_spec: { ruby: ["ruby-3.2", "ruby-3.1"], special-os: '*' }
     display_name: "${ruby}, ${special-os}"
     tasks:
       - name: "test"
 
   - matrix_name: "jruby"
-    matrix_spec: { ruby: ["jruby-9.4", "jruby-9.3"], all-os: ubuntu2204 }
+    matrix_spec: { ruby: ["jruby-10.0", "jruby-9.4", "jruby-9.3"], all-os: ubuntu2204 }
     display_name: "${ruby}, ${all-os}"
     tasks:
       - name: "test"
diff --git a/.evergreen/config/axes.yml.erb b/.evergreen/config/axes.yml.erb
index 99b691d0c..05949dde0 100644
--- a/.evergreen/config/axes.yml.erb
+++ b/.evergreen/config/axes.yml.erb
@@ -3,10 +3,15 @@ axes:
     display_name: OS
     values:
       - id: debian
-        display_name: "Debian 11"
-        run_on: debian11-small
+        display_name: "Debian 12"
+        run_on: debian12-small
         variables:
-          MACHINE: "debian11"
+          MACHINE: "debian12"
+      - id: "ubuntu2404"
+        display_name: "Ubuntu 24.04"
+        run_on: ubuntu2404-small
+        variables:
+          MACHINE: "ubuntu2204"
       - id: "ubuntu2204"
         display_name: "Ubuntu 22.04"
         run_on: ubuntu2204-small
@@ -21,11 +26,11 @@ axes:
   - id: "special-os"
     display_name: OS
     values:
-      - id: "ubuntu2204-arm64"
-        display_name: "Ubuntu 22.04 ARM64"
-        run_on: ubuntu2204-arm64-small
+      - id: "ubuntu2404-arm64"
+        display_name: "Ubuntu 24.04 ARM64"
+        run_on: ubuntu2404-arm64-small
         variables:
-          MACHINE: ubuntu2204-arm64
+          MACHINE: ubuntu2404-arm64
 
   - id: ruby
     display_name: Ruby Version
diff --git a/.evergreen/config/functions.yml.erb b/.evergreen/config/functions.yml.erb
index ba0ecc68f..5629d2a54 100644
--- a/.evergreen/config/functions.yml.erb
+++ b/.evergreen/config/functions.yml.erb
@@ -113,7 +113,7 @@ functions:
   "upload test results":
     - command: attach.xunit_results
       params:
-        file: ./src/*/build/test-results/TEST-*.xml
+        file: ./src/tmp/rspec.xml
 
   "run tests":
     - command: shell.exec
diff --git a/.evergreen/config/variants.yml.erb b/.evergreen/config/variants.yml.erb
index 40f27e921..d4a61541a 100644
--- a/.evergreen/config/variants.yml.erb
+++ b/.evergreen/config/variants.yml.erb
@@ -39,7 +39,7 @@ buildvariants:
       - name: "test"
 
   - matrix_name: "special-os"
-    matrix_spec: { ruby: <%= recent_rubies %>, special-os: '*' }
+    matrix_spec: { ruby: <%= recent_rubies - %w[ jruby-10.0 ] %>, special-os: '*' }
     display_name: "${ruby}, ${special-os}"
     tasks:
       - name: "test"
diff --git a/.evergreen/run-tests.sh b/.evergreen/run-tests.sh
index 770ee2c28..fac2776c2 100644
--- a/.evergreen/run-tests.sh
+++ b/.evergreen/run-tests.sh
@@ -17,6 +17,12 @@ set_env_ruby
 
 install_deps
 
+# TODO: move this to shared/shlib/set_env.sh
+export JAVA_HOME="/opt/java/jdk21"
+export SOURCE_VERSION=21
+export TARGET_VERSION=21
+# END TODO
+export CI=1
 echo "Running specs"
 bundle exec rake spec
 test_status=$?
diff --git a/.evergreen/update-evergreen-configs b/.evergreen/update-evergreen-configs
index 6c0fc5d3e..cddc1e3eb 100755
--- a/.evergreen/update-evergreen-configs
+++ b/.evergreen/update-evergreen-configs
@@ -75,7 +75,7 @@ module ConfigProcessor
 
   # these are used for testing against a few recent ruby versions
   def recent_rubies
-    @recent_rubies ||= %w[ ruby-3.2 ruby-3.1 jruby-9.4 ]
+    @recent_rubies ||= %w[ ruby-3.2 ruby-3.1 jruby-10.0 ]
   end
 
   # the most recently released, stable version of Ruby (make sure this
@@ -96,7 +96,7 @@ module ConfigProcessor
 
   # as above, but including the most recent JRuby release
   def sample_rubies
-    @sample_rubies ||= sample_mri_rubies + %w[ jruby-9.4 ]
+    @sample_rubies ||= sample_mri_rubies + %w[ jruby-10.0 ]
   end
 
   # older Ruby versions provided by 10gen/mongo-ruby-toolchain
@@ -106,7 +106,7 @@ module ConfigProcessor
 
   # all supported JRuby versions provided by 10gen/mongo-ruby-toolchain
   def jrubies
-    @jrubies ||= %w[ jruby-9.4 jruby-9.3 ]
+    @jrubies ||= %w[ jruby-10.0 jruby-9.4 jruby-9.3 ]
   end
 
   # all supported MRI ruby versions
diff --git a/.rspec b/.rspec
index aa6a1f446..2e2bcb135 100644
--- a/.rspec
+++ b/.rspec
@@ -1,3 +1,9 @@
---color
---format <%= ENV["CI"] ? 'Rfc::Riff' : 'Fuubar'%>
 --tty
+--colour
+<% if %w(1 true yes).include?(ENV['CI']&.downcase) %>
+--format RspecJunitFormatter
+--out tmp/rspec.xml
+--format 'Rfc::Riff'
+<% else %>
+--format Fuubar
+<% end %>
diff --git a/Gemfile b/Gemfile
index 6c66dae46..f88e124da 100644
--- a/Gemfile
+++ b/Gemfile
@@ -38,4 +38,5 @@ end
 group :test do
   gem 'fuubar'
   gem 'rfc'
+  gem "rspec_junit_formatter"
 end
diff --git a/spec/bson/int64_spec.rb b/spec/bson/int64_spec.rb
index efda1023d..7d741949d 100644
--- a/spec/bson/int64_spec.rb
+++ b/spec/bson/int64_spec.rb
@@ -100,7 +100,7 @@
         BSON::ByteBuffer.new(BSON::Int64.new(integer).to_bson.to_s)
       end
 
-      context "when on JRuby", if: BSON::Environment.jruby? do
+      context "when on JRuby", if: BSON::Environment.jruby? && RUBY_VERSION < '3.0.0' do
 
         it "deserializes to a Fixnum object" do
           expect(described_class.from_bson(bson).class).to be(Fixnum)
@@ -120,7 +120,7 @@
         BSON::ByteBuffer.new(integer.to_bson.to_s)
       end
 
-      context "when on JRuby", if: BSON::Environment.jruby? do
+      context "when on JRuby", if: BSON::Environment.jruby? && RUBY_VERSION < '3.0.0' do
 
         it "deserializes to a Fixnum object" do
           expect(described_class.from_bson(bson).class).to be(Fixnum)
diff --git a/src/main/org/bson_ruby/ByteBuf.java b/src/main/org/bson_ruby/ByteBuf.java
index 06f1e8e0d..9cdc31e64 100644
--- a/src/main/org/bson_ruby/ByteBuf.java
+++ b/src/main/org/bson_ruby/ByteBuf.java
@@ -564,7 +564,7 @@ public ByteBuf putInt64(ThreadContext context, IRubyObject value) {
       value = ((RubyFloat) value).truncate(context);
     }
     ensureBsonWrite(8);
-    this.buffer.putLong(((RubyInteger) value).getLongValue());
+    this.buffer.putLong(RubyNumeric.num2long(value));
     this.writePosition += 8;
     return this;
   }
diff --git a/src/main/org/bson_ruby/GeneratorExtension.java b/src/main/org/bson_ruby/GeneratorExtension.java
index 0f82c1e44..50558ecc2 100644
--- a/src/main/org/bson_ruby/GeneratorExtension.java
+++ b/src/main/org/bson_ruby/GeneratorExtension.java
@@ -25,6 +25,7 @@
 import org.jruby.Ruby;
 import org.jruby.RubyClass;
 import org.jruby.RubyInteger;
+import org.jruby.RubyNumeric;
 import org.jruby.RubyModule;
 import org.jruby.RubyString;
 import org.jruby.anno.JRubyMethod;
@@ -102,8 +103,7 @@ public static void extend(final RubyModule bson) {
   public static IRubyObject next(final IRubyObject generator) {
     RubyModule bson = generator.getRuntime().getModule(BSON);
     RubyClass objectId = bson.getClass(OBJECT_ID);
-    RubyInteger time = (RubyInteger) objectId.callMethod("timestamp");
-    return nextObjectId(generator, (int) time.getLongValue());
+    return nextObjectId(generator, (int) RubyNumeric.num2long(objectId.callMethod("timestamp")));
   }
 
   /**
@@ -118,7 +118,7 @@ public static IRubyObject next(final IRubyObject generator) {
    */
   @JRubyMethod(name = { "next", "next_object_id" })
   public static IRubyObject next(final IRubyObject generator, final IRubyObject time) {
-    return nextObjectId(generator, (int) ((RubyInteger) time).getLongValue() / 1000);
+    return nextObjectId(generator, (int) (RubyNumeric.num2long(time) / 1000));
   }
 
  /**
@@ -145,7 +145,7 @@ public static IRubyObject resetCounter(final IRubyObject generator) {
    */
   @JRubyMethod(name = { "reset_counter" })
   public static IRubyObject resetCounter(final IRubyObject generator, final IRubyObject value) {
-    counter.set((int) ((RubyInteger) value).getLongValue());
+    counter.set((int) RubyNumeric.num2long(value));
     return generator;
   }
 
diff --git a/src/main/org/bson_ruby/NativeService.java b/src/main/org/bson_ruby/NativeService.java
index 02eb11896..9938380dd 100644
--- a/src/main/org/bson_ruby/NativeService.java
+++ b/src/main/org/bson_ruby/NativeService.java
@@ -56,7 +56,7 @@ public class NativeService implements BasicLibraryService {
    * @since 2.0.0
    */
   public boolean basicLoad(final Ruby runtime) throws IOException {
-    RubyModule bson = runtime.fastGetModule(BSON);
+    RubyModule bson = runtime.getModule(BSON);
     GeneratorExtension.extend(bson);
 
     RubyClass byteBuffer = bson.defineClassUnder("ByteBuffer", runtime.getObject(), new ObjectAllocator() {