Re: upgrade ubuntu version
Please understand that, once you upgrade, you have no option to "roll back" to what you have now. So, if you encounter problems after the upgrade, which is not unusual, you will have to fix those to get a fully working system again.
The SAFE thing to do is to do a backup of your current install to an external drive, that way, if the upgrade encounters serious problems that you can't fix, you can "restore" back to what you have now.
Recommend using Clonezilla to do this.
Ubuntu 15.04 Mate, Mint 17.1; MS Win 8.1, Win10 TP.
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