diff --git a/src/PIL/GifImagePlugin.py b/src/PIL/GifImagePlugin.py
index 1d59edf091a..40239b9560d 100644
--- a/src/PIL/GifImagePlugin.py
+++ b/src/PIL/GifImagePlugin.py
@@ -37,11 +37,14 @@
 
 
 class ModeStrategy(IntEnum):
+    """.. versionadded:: 9.1.0"""
+
     AFTER_FIRST = 0
     ALWAYS = 1
     DIFFERENT_PALETTE_ONLY = 2
 
 
+#: versionadded:: 9.1.0
 PALETTE_TO_RGB = ModeStrategy.AFTER_FIRST
 
 # --------------------------------------------------------------------