diff --git a/CHANGELOG b/CHANGELOG
index 231ce4c..08accf5 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -13,12 +13,13 @@ The rules for this file:
   * accompany each entry with github issue/PR number (Issue #xyz)
 
 ------------------------------------------------------------------------------
-04/30/2022 orbeckst, IAlibay
+05/21/2022 orbeckst, IAlibay
 
   * 1.0.0
 
   Changes
 
+  * API-stable release
   * deprecated and buggy CCP4 module was removed (#107, #50)
   * gridDataFormats now follows NEP29 (#102)
   * removed support for Python 2.7 and Python <3.8 (#102)
diff --git a/setup.py b/setup.py
index e378972..64cfb7e 100644
--- a/setup.py
+++ b/setup.py
@@ -21,7 +21,7 @@
       url="https://github.com/MDAnalysis/GridDataFormats",
       download_url="https://github.com/MDAnalysis/GridDataFormats/releases",
       keywords="science array density",
-      classifiers=['Development Status :: 5 - Mature',
+      classifiers=['Development Status :: 6 - Mature',
                    'Environment :: Console',
                    'Intended Audience :: Science/Research',
                    'License :: OSI Approved :: GNU Lesser General Public License v3 (LGPLv3)',