https://us.community.samsung.com/t5/Legacy-S-Phones/Background-in-messages-does-not-change-when-downloading-a-new/m-p/1657906/highlight/true
Solved: Re: Theme in messaging - Samsung Community - 1657772
Jun 30, 2022 - did it work lol? - 1657772
samsung communitysolvedthememessaging