"No Compatible Version Available" when actually there's one available.

Hi, I'm new to the Aternos, but I've wanted do use the "Travellers backpack" mod in my server, and there is a Aternos page on the "mods" menu, but it says that there's no compatible version, even tho I got it installed and running on single player AND it's for 1.15.2. What should I do or i just need Aternos to update this?