I have particular forums set up where I stick all my topics I want to archive. When I upgraded from 3.4.9 to 4.1.19.1 these forums will no longer allow me to move topics to them. They are greyed out when I try to move a topic to them. I've turned off archiving and I've check the permissions and I'm set as an admin with no restrictions so not sure what's going on.

Best to open a support ticket so someone from IPS can check it out on your site directly. 

I figured this out. Permission on the forum was set at See Forum, Read Topics but not any other permission. In order to move topics to the forum I had to also check Post New Topics.