block are white and have red question marks

[Becca M]

hi i am not sure if anyone else is having trouble but as soon as i updated my game i logged into my server and there are a lot of things that are white with red question marks on them. i went to the wiki and done the /fixmapping applyall command but it didn't fix the problem. Also my single player game crashed said i need to remove the mods

[Benjamin Bishop]

Same issue, I'm guessing the mod developer needs to update there mods.