added GL_ARB_texture_non_power_of_two
diff --git a/docs/RELNOTES-5.1 b/docs/RELNOTES-5.1
index d061991..3c7451c 100644
--- a/docs/RELNOTES-5.1
+++ b/docs/RELNOTES-5.1
@@ -63,6 +63,8 @@
 GL_ARB_occlusion_query
    Useful for visibility-based culling.
 
+GL_ARB_texture_non_power_of_two
+   Removes the restriction that texture dimensions must be powers of two.
 
 
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