Decided to update the User Guide and hel files for PCDB SuDoku Solver while thinking about what to do about licencing. I've finally decided that, in the light of Google's edict that copy protection is deprecated, it's as well to bite the bullet and incorporate licencing in from Day 1. So Day 1 has been postponed for a few days while I grapple with the Android APIs and test mechanisms to make sure it lets legitimate users continue to use the app while confining unlicenced ones to the 'LITE' version.