Hi all!
I wanted to know how advanced currencies impacts already exisiting opportunities. 
I tested it in one sandbox and after the new currency is enabled, all opportunities that have been created up to this point are not affected and still use the previous currency. My understanding was that only closed opportunities should stay with the previous currency and open opportunities use the new one (so basically the 'CloseDate' is taken into account).
I also created a new opportunity after the new currency became active and this one correctly used the new one. 
This makes it look like instead of the CloseDate the CreatedDate is taken into account for previous or new currency.
Can someone enlighten me please? :)
Thanks in advance!