Minecraft:dataserializers issue

[N1ght]

Hi there,

I've had this issue for the past months or so, and I cannot seem to join back into my modded server. The mods I used are all the same, as well as the mod version (running 1.12.2 14.23.5.2847, Aternos)
Whenever I test the mods on a singleplayer world, it works just fine, but when I join my server it says "missing registries: minecraft:dataserializers", is there something I can do to fix this rather than going into 1.13.2?

[Ugdhar]

1.12 is no longer supported due to age.

Please update to a modern (1.14.4/1.15.2) version to receive support.

 

More information on supported versions can be found in the LTS link at the top of every page.