I'm assuming for some reason you have a valid study permit but not a valid TRV. In that case, CIC says you should apply for a new visa only after you receive your new permit, and not simultaneously. (that makes sense, because people in CPC-Ottawa who will issue your new visa need to base their decision on an approval of your new permit which is to be made by another officer at CPC-Vegreville; so the latter should be finalized before the former can start, right?)
My recommendation is: wait for your new permit, then apply for a new TRV. If you get it in time, you can go to your conference.
German consulate will check if you have the right documents to return to Canada after your proposed length of stay in Europe. So if you don't have a valid visa in your passport they might get mad! you can e-mail them and ask, they're pretty fast in replying, but be sure not to confuse them with a long and detailed email!
And finally, if you get your immigrant visa soon enough, you can just delay your landing until after you come back from Germany. I don't know why on this website everyone is in such a RUSH to land the moment they get their visas, as if CIC might change their mind lol
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