Hi Ayub,

Migration process is actually quite simple. All you need to do is head to easyblog backend > migrator > k2 and follow the instruction from there. We can help you with the migration as well but it is always advisable for you to perform a backup of your server and database first before the process.

I use Additional Categories for K2: http://extensions.joomla.org/extension/additional-categories-for-k2 . You support this too?

Yes easyblog 5 does support multi-categories for one blog post.