diff --git a/pyproject.toml b/pyproject.toml
index 8b886e3..81a9108 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,6 +4,7 @@ description = "Simple tools for astronomical spectral energy distributions, part
 authors = [{ name = "Benjamin Johnson", email = "benjamin.johnson@cfa.harvard.edu" }]
 readme = "README.rst"
 license = { text = "MIT License" }
+requires-python = ">=3.9"
 classifiers = [
     "Development Status :: 5 - Production/Stable",
     "Intended Audience :: Developers",
@@ -11,9 +12,18 @@ classifiers = [
     "License :: OSI Approved :: MIT License",
     "Operating System :: OS Independent",
     "Programming Language :: Python",
+    "Programming Language :: Python :: 3",
+    "Programming Language :: Python :: 3.9",
+    "Programming Language :: Python :: 3.10",
+    "Programming Language :: Python :: 3.11",
+    "Programming Language :: Python :: 3.12",
+    "Programming Language :: Python :: 3.13",
 ]
 dynamic = ["version"]
-dependencies = ["numpy", "astropy"]
+dependencies = [
+    "numpy", 
+    "astropy"
+]
 
 [build-system]
 requires = ["setuptools>=42", "wheel", "setuptools_scm"]
diff --git a/sedpy/observate.py b/sedpy/observate.py
index 893e1aa..8e37235 100644
--- a/sedpy/observate.py
+++ b/sedpy/observate.py
@@ -13,10 +13,7 @@
     from numpy import trapz as trapezoid
 
 import os
-try:
-    from pkg_resources import resource_filename, resource_listdir
-except(ImportError):
-    pass
+from importlib.resources import files
 from .reference_spectra import vega, solar, sedpydir
 
 
@@ -90,8 +87,9 @@ def __init__(self, kname='sdss_r0', nick=None,
         if directory is None:
             loc = os.path.join('data', 'filters', kname + '.par')
             try:
-                self.filename = resource_filename("sedpy", loc)
-            except:
+                data_files = files('sedpy') / 'data' / 'filters'
+                self.filename = str(data_files / (kname + '.par'))
+            except Exception:
                 self.filename = os.path.join(sedpydir, loc)
         else:
             self.filename = os.path.join(directory, kname+'.par')
@@ -815,11 +813,12 @@ def list_available_filters():
     have been installed in the sedpy/data/filters/ directory.
     """
     try:
-        names = resource_listdir('sedpy', '/data/filters/')
-    except:
-        names = os.listdir(os.path.join(sedpydir, '/data/filters/'))
+        data_files = files('sedpy') / 'data' / 'filters'
+        names = [f.name for f in data_files.iterdir() if f.is_file()]
+    except Exception:
+        names = os.listdir(os.path.join(sedpydir, 'data', 'filters'))
 
-    parfiles = [n.replace('.par', '') for n in names if n[-4:] == '.par']
+    parfiles = [n.replace('.par', '') for n in names if n.endswith('.par')]
     parfiles.sort()
     return parfiles
 
diff --git a/sedpy/reference_spectra.py b/sedpy/reference_spectra.py
index a047ab7..8cd9378 100644
--- a/sedpy/reference_spectra.py
+++ b/sedpy/reference_spectra.py
@@ -7,10 +7,7 @@
 
 import numpy as np
 import os
-try:
-    from pkg_resources import resource_filename
-except ImportError:
-    pass
+from importlib.resources import files
 try:
     import astropy.io.fits as pyfits
 except ImportError:
@@ -28,8 +25,9 @@
     # This is from stsci calspec database ("calspec_ascii_review")
     # C.f. https://ui.adsabs.harvard.edu/abs/2007ASPC..364..315B/abstract
     # C.f. https://ui.adsabs.harvard.edu/abs/2014AJ....147..127B/abstract
-    vega_file = resource_filename('sedpy', 'data/alpha_lyr_stis_005.fits')
-except:
+    data_files = files('sedpy') / 'data'
+    vega_file = str(data_files / 'alpha_lyr_stis_005.fits')
+except Exception:
     vega_file = os.path.join(sedpydir, 'data', 'alpha_lyr_stis_005.fits')
 
 # This file should be in AA and erg/s/cm^2/AA
@@ -43,8 +41,9 @@
                      'spectrum at {0}'.format(vega_file))
 
 try:
-    solar_file = resource_filename('sedpy', 'data/sun_kurucz93.fits')
-except:
+    data_files = files('sedpy') / 'data'
+    solar_file = str(data_files / 'sun_kurucz93.fits')
+except Exception:
     solar_file = os.path.join(sedpydir, 'data', 'sun_kurucz93.fits')
 
 # conversion to d=10 pc from 1 AU