First of all I need help to upgrade a older K2 version to the new one but how can I now what is the old version I installed last year 

Second I have the Simple Image Gallery Plugin enabled but in the K2 information tab it shows Simple Image Gallery Plugin Not installed what about

And now my big problem Is there a way to sort items by tags
I have 360 items added in 28 alphabetical categories and 85 tags - how to sort items by tags?
I created the tags and now I want to put them in alphabetical order but I find no way to do that Is this possible or I have to start again the work
Should I make new 85 categories? but how to ad already created items to new categories that I should create - may a item belong to several categories?

Please help - thanks