I am the author of Renew.
Renew is an open source macOS project to help Mac Admins remind their users when its time to reboot.
Renew is a highly configurable program both in behavior and design, utilizing SwiftDialog to make a visually appealing user interface.
The user experience and operation is defined by an MDM profile, and the project consists of a shell script and a simple Launch Agent.
The BigMacAdmin Blog 