Hello Tronak,
To verify, have you had a chance to test another Apple AV HDMI adapter with these devices? We ask, since the issue is happening with multiple devices and seems to be following the adapter itself. Another option, would be to test the adapter on a device that is on an iOS software version that is a known working version of the iOS software with this adapter. This will help to isolate the issue specifically to the adapter or iOS software.
Also, check out this link with more information on how to use Digital AV Adapters with your iPhone or iPad: About Apple Digital AV Adapters for iPhone, iPad, and iPod touch - Apple Support.
Get connected
Connect your iPhone, iPad, or iPod touch to a display:
1. Plug your Digital AV or VGA adapter into the charging port on the bottom of your iOS device.
2. Connect an HDMI or VGA cable to your adapter.
3. Connect the other end of your HDMI or VGA cable to your secondary display (TV, monitor, or projector).
4. Turn on your secondary display.
5. If necessary, switch to the correct video source on your secondary display. If you need help, use your display's manual.
Now the screen on your iPhone, iPad, or iPod touch should appear2 on your TV, display, or projector.
Be sure to also check out the section labeled "Get help" from that page, as it offers other great steps to try that may help to resolve these issues.
Kind regards!