Timeslips 2015 is not supported on windows 10. It may work but we have seen issues. The most noticeable issue is extra space at the beginning of each slip description. If you edit the slip the space increases. 
Timeslips 2020 is available through consultants like me until September. It is fully supported on Windows 10. It has been announced as the last perpetual version. You can also go to Timeslips Premium at any time. This is a subscription version with additional features and support.