diff --git a/src/or/routerparse.c b/src/or/routerparse.c
index aed4fd131e..001c4d6c7f 100644
--- a/src/or/routerparse.c
+++ b/src/or/routerparse.c
@@ -572,7 +572,6 @@ static int check_signature_token(const char *digest,
                                  int flags,
                                  const char *doctype);
 static crypto_pk_env_t *find_dir_signing_key(const char *str, const char *eos);
-static int tor_version_same_series(tor_version_t *a, tor_version_t *b);
 
 #undef DEBUG_AREA_ALLOC
 
@@ -4556,7 +4555,7 @@ tor_version_compare(tor_version_t *a, tor_version_t *b)
 
 /** Return true iff versions <b>a</b> and <b>b</b> belong to the same series.
  */
-static int
+int
 tor_version_same_series(tor_version_t *a, tor_version_t *b)
 {
   tor_assert(a);
diff --git a/src/or/routerparse.h b/src/or/routerparse.h
index 8b8cde25f6..527de5dc8b 100644
--- a/src/or/routerparse.h
+++ b/src/or/routerparse.h
@@ -47,6 +47,7 @@ version_status_t tor_version_is_obsolete(const char *myversion,
 int tor_version_parse(const char *s, tor_version_t *out);
 int tor_version_as_new_as(const char *platform, const char *cutoff);
 int tor_version_compare(tor_version_t *a, tor_version_t *b);
+int tor_version_same_series(tor_version_t *a, tor_version_t *b);
 void sort_version_list(smartlist_t *lst, int remove_duplicates);
 void assert_addr_policy_ok(smartlist_t *t);
 void dump_distinct_digest_count(int severity);