diff --git a/data.c b/data.c
index 3403b06..cbdfea4 100644
--- a/data.c
+++ b/data.c
@@ -19,7 +19,7 @@ double db_layout = 2.3;
 
 int db_upgrade(d_char **error);
 
-int srv_open(char *basedir)
+int srv_open(char *basedir, int auto_upgrade)
 /* opens a server */
 {
     int ret = 0;
@@ -69,7 +69,14 @@ int srv_open(char *basedir)
                     error = xs_fmt("DEBUG level set to %d from environment", dbglevel);
                 }
 
-                ret = db_upgrade(&error);
+                if (auto_upgrade)
+                    ret = db_upgrade(&error);
+                else {
+                    if (xs_number_get(xs_dict_get(srv_config, "layout")) < db_layout) {
+                        ret   = 0;
+                        error = xs_fmt("ERROR: db layout changed - execute 'snac upgrade' first");
+                    }
+                }
             }
 
         }
diff --git a/main.c b/main.c
index 8e3dbd2..862f30d 100644
--- a/main.c
+++ b/main.c
@@ -16,6 +16,7 @@ int usage(void)
     printf("Commands:\n");
     printf("\n");
     printf("init [{basedir}]                 Initializes the database\n");
+    printf("upgrade {basedir}                Upgrade to a new version\n");
     printf("adduser {basedir} [{uid}]        Adds a new user\n");
     printf("httpd {basedir}                  Starts the HTTPD daemon\n");
     printf("purge {basedir}                  Purges old data\n");
@@ -76,6 +77,19 @@ int main(int argc, char *argv[])
         return initdb(basedir);
     }
 
+    if (strcmp(cmd, "upgrade") == 0) {
+        int ret;
+
+        /* database upgrade */
+        if ((basedir = GET_ARGV()) == NULL)
+            return usage();
+
+        if ((ret = srv_open(basedir, 1)) == 1)
+            srv_log(xs_dup("OK"));
+
+        return ret;
+    }
+
     if (strcmp(cmd, "markdown") == 0) {
         /* undocumented, for testing only */
         xs *c = xs_readall(stdin);
@@ -88,7 +102,7 @@ int main(int argc, char *argv[])
     if ((basedir = GET_ARGV()) == NULL)
         return usage();
 
-    if (!srv_open(basedir)) {
+    if (!srv_open(basedir, 0)) {
         srv_log(xs_fmt("error opening database at %s", basedir));
         return 1;
     }
diff --git a/snac.h b/snac.h
index 6edf50c..bdbdade 100644
--- a/snac.h
+++ b/snac.h
@@ -24,7 +24,7 @@ double ftime(void);
 void srv_debug(int level, d_char *str);
 #define srv_log(str) srv_debug(0, str)
 
-int srv_open(char *basedir);
+int srv_open(char *basedir, int auto_upgrade);
 void srv_free(void);
 
 typedef struct _snac {