PicSender 3x has been temporarily withdrawn from downloading due to lockup problems with some custom versions of grbl. Until I can discover the cause of the problems, PicSender 188.8.131.52 will be available for updates and/or new users. I apologize for this inconvenience.
EDIT: August 3, 2019 - please ignore the above announcement. PicSender 3.1.0 appears apparently stable now after a few weeks in Beta release.