It's worth to update the app to the new version

Answer 1

If you're asking if you should update your SoloLearn app, then yes, I would do that any time it offers an update. This means they've either fixed bugs, added content or courses, etc...

Answer 2

If you won't waste any time or money on this, then updating SoloLearn is recommended. You can wait three or four times for a newer versions to be available and download the latest one if you want to be so economical though.