1 files changed, 1 insertions, 1 deletions
diff --git a/README.md b/README.md
index 1657448..db95f95 100644
--- a/README.md
+++ b/README.md
@@ -184,7 +184,7 @@ are prefixed with 'Module_'.
 | **_Module_19_b_1_** | yes    | 465  | |
 | 19_b_2         | yes    |      | |
 | 19_b_3         | yes, in 19_b_2  |      | |
-| **_23_a_1_**   |        | 529  | 23. GUI programming with gtk2hs|
+| **_23_a_1_**   | yes    | 529  | 23. GUI programming with gtk2hs|
 | 23_a_2         |        |      | |
 | 23_a_3         |        |      | |
 | **_24_a_1_**   |        | 542  | 24. Concurrent and multicore programming |