Re: NEM (XEM) Official Thread - New Update 0.6.43 - Please Update Your Nodes
Oh okay, thanks for this information. I had a problem starting harvesting after an update and someone on nem forum told me, that it is necessary to stop and start the delegate harvesting :/ Now I know it better 
You should keep your old wallet instead of importing your private key in a new one.
Rigel is right. The delegate harvester is attached to that wallet. So if you save it, you can even move to a different computer and not have to stop and start it again. Much easier too than having to import the key each time. http://blog.nem.io/how-to-find-export-or-delete-your-wallet-and-address-book-file/
Argh...what I don't like is that I always need to stop and start harvesting after an update. it costs 12 hours (6hr for stop, and 6 hrs to start again). 
You should keep your old wallet instead of importing your private key in a new one.
Rigel is right. The delegate harvester is attached to that wallet. So if you save it, you can even move to a different computer and not have to stop and start it again. Much easier too than having to import the key each time. http://blog.nem.io/how-to-find-export-or-delete-your-wallet-and-address-book-file/