diff --git a/meshtastic/config.options b/meshtastic/config.options
index 4490f082..22dcc88a 100644
--- a/meshtastic/config.options
+++ b/meshtastic/config.options
@@ -1,3 +1,6 @@
+# longest current is 45 chars, plan with a bit of buffer
+*DeviceConfig.tzdef max_size:65
+
 *NetworkConfig.wifi_ssid max_size:33
 *NetworkConfig.wifi_psk max_size:65
 *NetworkConfig.ntp_server max_size:33
diff --git a/meshtastic/config.proto b/meshtastic/config.proto
index 5b936493..77e1bef8 100644
--- a/meshtastic/config.proto
+++ b/meshtastic/config.proto
@@ -180,6 +180,11 @@ message Config {
      * Disables the triple-press of user button to enable or disable GPS
      */
     bool disable_triple_click = 10;
+
+    /*
+     * POSIX Timezone definition string from https://github.com/nayarsystems/posix_tz_db/blob/master/zones.csv.
+     */
+    string tzdef = 11;
   }
 
   /*