Hi,
im looking for several ways to “ungoogle” my Smartphone.
With Nextcloud its quite easy to move Files/Contacts/Calendar to a self-hosted Service.
Another thing i would like to have is a open and self-hosted replacement for the Google DeviceManager.
With that Service you can do things like Locate/Lock/Wipe your Device remotely via an Webinterface in case of Theft.
It would be really neat to have something like that integrated into Nextcloud.
I’ve found an Project which aimed to do exactly this. (Standalone PHP Application)
Unfortunately is abandoned since ~2014
It would be very nice to find someone who has the necessary PHP (+Java) skills and Time to implement/maintain this as an Nextcloud Application 
Open Device Manager, or ODM, is a fully free, open source, end-to-end encrypted alternative to Google’s Android Device Manager
ODM was created because of the lack of fully open source and secure device managers on the market. While there are solutions that offer open source web components, the Android Applications are not, and are known to use Google Analytics or ad networks that pull information such as IP address, all of which eliminate 100% privacy. ODM overcomes this by offering everything up for grabs on github. We will also be submitting the github repository to F-Droid, an alternative App Store that compiles open source applications directly from github, so you know you.re getting a safe APK.
Features include:
Open source web interface
Open source Android Application
All notifications/commands sent through Google are encrypted first
Full AJAX interface
10 second server install
Multi-user support
Multi-device per user support
Last and previous locations
Google maps integration
Lock device
Take photos with rear and front cameras
Alert ringer to locate the phone
Receive an SMS to identify insertion of new SIM
Send a custom notification
Wipe device
Log of all previous activity
