diff --git a/src/vendor/cigraph/src/core/bitset_list.c b/src/vendor/cigraph/src/core/bitset_list.c
index 3fdd36b0f1..4b3ec576be 100644
--- a/src/vendor/cigraph/src/core/bitset_list.c
+++ b/src/vendor/cigraph/src/core/bitset_list.c
@@ -35,6 +35,7 @@
 static igraph_error_t igraph_i_bitset_list_init_item(
     const igraph_bitset_list_t* list, igraph_bitset_t* item
 ) {
+    IGRAPH_UNUSED(list);
     return igraph_bitset_init(item, 0);
 }
 
diff --git a/src/vendor/igraph_version.h b/src/vendor/igraph_version.h
index 7288d3643a..d6d24e25f1 100644
--- a/src/vendor/igraph_version.h
+++ b/src/vendor/igraph_version.h
@@ -28,11 +28,11 @@
 
 __BEGIN_DECLS
 
-#define IGRAPH_VERSION "0.10.15-20-g8cdfd787c"
+#define IGRAPH_VERSION "0.10.15-21-g5e3c56c6a"
 #define IGRAPH_VERSION_MAJOR 0
 #define IGRAPH_VERSION_MINOR 10
 #define IGRAPH_VERSION_PATCH 15
-#define IGRAPH_VERSION_PRERELEASE "20-g8cdfd787c"
+#define IGRAPH_VERSION_PRERELEASE "21-g5e3c56c6a"
 
 IGRAPH_EXPORT void igraph_version(const char **version_string,
                                   int *major,