I think that table to remember the version models which registered from assemblies. Try to remove or modify them, clear ASP.NET cache, restart site to make the CMS synchronize model again.
NOTE: You should backup your database first before doing these things, it is dangerous
We where planning to update Episervfer.Forms from version 4.5 to 4.7 but we had to revert the change (because Episerver forms 4.7 doesn't allow form submitions unless session state is enabled or form data is stored). After the original nuget package (version 4.5) was restored, I noticed following message in log:
"EPiServer.DataAbstraction.RuntimeModel.Internal.ContentTypeModelRegister: Changes in the model were ignored because its version(18.104.22.168) is lower than version in the database(4.7)".
I'm assuming that this is caused by the difference in nuget package assembly version and version stored to databases tblContentType.ModelType.
Is there a way to downgrade the databases model type version back to nuget packages version?