Gemfile.lock update, typecheck/lint error fix.

Gemfile.lock

@@ -297,8 +297,6 @@ GEM
       websocket-extensions (>= 0.1.0)
     websocket-extensions (0.1.4)
     zeitwerk (2.2.0)
-    zero_downtime_migrations (0.0.7)
-      activerecord
 
 PLATFORMS
   ruby
@@ -340,7 +338,6 @@ DEPENDENCIES
   smarf_doc!
   tzinfo
   valid_url
-  zero_downtime_migrations
 
 RUBY VERSION
    ruby 2.6.5p114

frontend/devices/components/fbos_settings/ota_time_selector/index.tsx

@@ -6,6 +6,9 @@ import { edit, save } from "../../../../api/crud";
 
 const IMMEDIATELY = -1;
 
+// tslint:disable-next-line:no-null-keyword
+const UNDEFINED = null as unknown as undefined;
+
 const OTA_TIMES: Record<number, DropDownItem> = {
   0: { label: "at Midnight", value: 0 },
   1: { label: "at 1 AM", value: 1 },
@@ -52,7 +55,7 @@ export const OtaTimeSelector = ({ onChange, value }: OtaTimeSelectorProps): JSX.
   const cb = (ddi: DropDownItem) => {
     const v = parseInt("" + ddi.value, 10);
 
-    onChange((v == IMMEDIATELY) ? null : v);
+    onChange((v == IMMEDIATELY) ? UNDEFINED : v);
   };
 
   const list = Object