Yes, you can. Again, please note that each key has a maximum number of uses/updates assigned to it. See the previous FAQ item.

A key expires either if the expiration date or the maximum number of uses for that key has been reached. One use is counted when you update to the latest version/build ComfortUpdate.

LimeSurvey is under GPL so every feature in LimeSurvey will always be open to the general public.However, there are feature components of the software like template editing, advanced survey export and so on that may get paid extras...

Yes, LimeSurvey software is free open source - everyone can use, modify and distribute it for commercial, private and educational purposes under the GPL license v3(exception: the name and logo LimeSurvey is trademarked, so please...