Well this is not nice.
I upgraded to newest community mod - 0.26.02 and it realy sucks that there is not a " downgrade " option rn, because there are only 4-5 people who has the newest mod update, and basicaly you can't play with anyone unless they will join your mod hell, where just 5 people has this mod.
As discussed with a friend - this mod upgrade thing it will make game waiting time forever. Because people will not upgrade. Many will not even download the first mod, because they are too dumb in computer stuff or because they don't speak english enough to understand what is happening.
My offer as a solution:
In most of the games, when you turn on the game, there is a screen "There is an update, please download it" and then you just press a button "Yes" and it downloads. Can you make something like that for 0ad? Like... make it easier for players. They enter game-> You tell them there is an update -> They press a button -> Mod is downloaded and enabled.