The list of blocked instances might changed (check [myinstancena.me]/instances) and blocked users. Not every instances shows downvote. This make the all feed slighty different.
Your local feed will change a lot. In there you only see your instances community slrpnk.net is slorpunk oriented, feddit.it is italian speaking community and so on. Your subscription feed will remain the same.
The list of possible interface will be different. That’s on web browser but I don’t know it affect application users.