It is on the first page of my mobile app post: viewtopic.php?f=2&t=154
It is also in the mobile app itself on the about page. This is accessed via the side menu on the top right.
This should work fine though: https://www.paypal.com/cgi-bin/webscr?cmd=_xclick&[email protected]&item_name=OpenSprinkler%20Controller&page_style=PayPal&no_shipping=1¤cy_code=USD&lc=US&bn=OS_Donations&charset=UTF%2d8
Thank you!