diff --git a/.github/workflows/standard.yml b/.github/workflows/standard.yml
index ad96941a4..c95432722 100644
--- a/.github/workflows/standard.yml
+++ b/.github/workflows/standard.yml
@@ -29,10 +29,10 @@ jobs:
           - macOS
         gap-version:
           - master
+          - v4.16
           - v4.15
           - v4.14
           - v4.13
-          - v4.12
         configflags:
           - "--disable-hpcombi"
 
diff --git a/makedoc.g b/makedoc.g
index a115b7b98..6378ece13 100644
--- a/makedoc.g
+++ b/makedoc.g
@@ -124,7 +124,7 @@ XMLEntities.bbN := """<Alt Not="Text"><M>\mathbb{N}</M></Alt>
 
 # The actual call to AutoDoc
 
-AutoDoc("semigroups", rec(
+AutoDoc(rec(
     autodoc := rec(scan_dirs := ["gap/tools/", "gap/attributes"]),
     gapdoc := rec(
         LaTeXOptions := rec(EarlyExtraPreamble := """
diff --git a/src/to-cpp.hpp b/src/to-cpp.hpp
index 1ee71bb61..d7bfdce0c 100644
--- a/src/to-cpp.hpp
+++ b/src/to-cpp.hpp
@@ -390,7 +390,7 @@ namespace gapbind14 {
     static gap_tnum_type constexpr gap_type = T_STRING;
 
     cpp_type operator()(Obj o) const {
-      if (TNUM_OBJ(o) != T_STRING && TNUM_OBJ(o) != T_STRING + IMMUTABLE) {
+      if (!IS_STRING_REP(o)) {
         ErrorQuit("expected string but got %s!", (Int) TNAM_OBJ(o), 0L);
       }
       std::string stype = std::string(CSTR_STRING(o));
@@ -412,7 +412,7 @@ namespace gapbind14 {
 
     cpp_type operator()(Obj o) const {
       using Order = libsemigroups::Order;
-      if (TNUM_OBJ(o) != T_STRING && TNUM_OBJ(o) != T_STRING + IMMUTABLE) {
+      if (!IS_STRING_REP(o)) {
         ErrorQuit("expected string but got %s!", (Int) TNAM_OBJ(o), 0L);
       }
       std::string_view stype = CSTR_STRING(o);