As reported in a reddit post and confirmed in a github discussion, Simple Mobile Tools is being sold to ZippoApps which is known for shady business practices.
It is not yet clear whether they will make the app suite closed source (which would infringe the rights of all contributors since they contributed under the GPLv3 license).
In response to that situation, one of the main contributors forked the project under the name FossifyX and will continue to work on it.
Just read the entire thread. This is sad. I was about to recommend the contacts app to my Dad, glad I didn’t.
There is also another fork for the contacts app called Simple Contacts Pro SE by Stephan Ritscher.