diff --git a/c/libraries.c b/c/libraries.c
index 36584c0..fa207c7 100644
--- a/c/libraries.c
+++ b/c/libraries.c
@@ -50,8 +50,8 @@ struct builtin_library {
 // Up Scheme libraries
 #define UP_2019 (1 << 20)
 
-const char *upscheme_stable_specs[] = { 0 };
-const char upscheme_unstable_spec[] = "2019";
+const int upscheme_stable_specs[] = { 0 };
+const int upscheme_unstable_spec = 2019;
 
 static struct builtin_procedure builtin_procedures[] = {
 #if 0
diff --git a/c/main.c b/c/main.c
index 9ae4452..58e9d7a 100644
--- a/c/main.c
+++ b/c/main.c
@@ -56,11 +56,11 @@ static value_t build_c_type_bits_list(void)
 static value_t build_stable_specs_list(void)
 {
     struct accum acc;
-    const char **sp;
+    const int *p;
 
     accum_init(&acc);
-    for (sp = upscheme_stable_specs; *sp; sp++) {
-        accum_elt(&acc, string_from_cstr(*sp));
+    for (p = upscheme_stable_specs; *p; p++) {
+        accum_elt(&acc, fixnum(*p));
     }
     return acc.list;
 }
@@ -217,7 +217,7 @@ static value_t get_version_alist(void)
         accum_name_value(&acc, "upscheme/stable-specs",
                          build_stable_specs_list());
         accum_name_value1(&acc, "upscheme/unstable-spec",
-                          string_from_cstr(upscheme_unstable_spec));
+                          fixnum(upscheme_unstable_spec));
     }
     return acc.list;
 }
diff --git a/c/scheme.h b/c/scheme.h
index 7b75b31..9a68c37 100644
--- a/c/scheme.h
+++ b/c/scheme.h
@@ -1016,8 +1016,8 @@ extern const char env_release_date[];
 
 //// #include "libraries.h"
 
-extern const char *upscheme_stable_specs[];
-extern const char upscheme_unstable_spec[];
+extern const int upscheme_stable_specs[];
+extern const int upscheme_unstable_spec;
 
 value_t builtin_import(value_t *args, uint32_t nargs);