diff --git a/.github/workflows/mingw.yml b/.github/workflows/mingw.yml
index 773bb775033d41..911381622a8c65 100644
--- a/.github/workflows/mingw.yml
+++ b/.github/workflows/mingw.yml
@@ -63,7 +63,7 @@ jobs:
       )}}
 
     steps:
-      - uses: msys2/setup-msys2@40677d36a502eb2cf0fb808cc9dec31bf6152638 # v2.28.0
+      - uses: msys2/setup-msys2@fb197b72ce45fb24f17bf3f807a388985654d1f2 # v2.29.0
         id: msys2
         with:
           msystem: UCRT64
diff --git a/configure.ac b/configure.ac
index 363748567500a1..47f8b79b038fbe 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1804,10 +1804,6 @@ RUBY_DECL_ATTRIBUTE([__nonnull__(n)], [RUBY_FUNC_NONNULL(n,x)], [rb_cv_func_nonn
 
 RUBY_APPEND_OPTION(XCFLAGS, -DRUBY_EXPORT)
 
-AC_ARG_ENABLE(mathn,
-    AS_HELP_STRING([--enable-mathn], [enable canonicalization for mathn]),
-    [AC_MSG_ERROR([mathn support has been dropped])])
-
 AC_CACHE_CHECK(for function name string predefined identifier,
     rb_cv_function_name_string,
     [AS_CASE(["$target_os"],[openbsd*],[