As of Version 1.13 Marketplace worlds have the option to don't get updated anymore to keep important game functions.

But with this introduction every Marketplace world that was uploaded prior to 1.13 is locked at this version, because the game used 1.13.0 as default value instead of "*". 
Because of this almost all Marketplace worlds are unintentionally stuck now and don't receive updates anymore.

More infos how the version locking works:https://feedback.minecraft.net/hc/en-us/articles/360033322932-Minecraft-Beta-1-13-0-13-Xbox-One-Windows-10-Android-

If this is not clear enough I can try to explain it better.
(Sorry for bad English)