Same format of mail sent to me. If you family composition has not changed i.e. you have not had a new baby or none is lost, you are not divorced (God forbids). Just send them a cover letter like I did that your family composition did not change and you can even attach a copy of the form IMM8 (generic form) you filled when you initially applied. Hope this helps.
Beloved e-family, my family received Visas & CoPR today, Rejoice with us, I pray all our dreams come through, everyone expecting one update or the other, the Lord God almighty who did mine will surprise you big time in Jesus most precious name, ...539 days dream is in our hands today. Please enjoy this musical and give praise to the Lord God Almighty, that picks a man from the dung hill and places him in the palace with kings.... Enjoy this piece by Sinach
https://www.youtube.com/watch?v=nuBA5YSsWUI