diff --git a/README.md b/README.md
index f7d28dae920872c30f7944f011f8257f222e48ca..e5728e5fc9ad5ca3c28573cc9cd2db4d8c073fd8 100644
--- a/README.md
+++ b/README.md
@@ -62,7 +62,7 @@ If you've installed Hammer system-wide, you can use `pkg-config` in the usual wa
 
 To learn about hammer check
 * the [user guide](https://github.com/UpstandingHackers/hammer/wiki/User-guide)
-* [Hammer Primer](https://github.com/sergeybratus/HammerPrimer)
+* [Hammer Primer](https://github.com/sergeybratus/HammerPrimer) (outdated in terms of code, but good to get the general thinking)
 * [Try Hammer](https://github.com/sboesen/TryHammer)
 
 Examples