Android 2. 3 and newer versions support a built in SIP/VoIP functionality. This widget has two buttons: the left one gives you a shortcut to the SIP settings.
The antivirus report has confirmed that the app is totally safe for usage. Robert Siebeck designed SIP Switch Widget that lies within the Tools category. The overall score for this application is 4.2 on Google Play.
The latest update was on Nov 30, 2017 and the app was downloaded and installed by over 10K users. Get the free .apk setup package of SIP Switch Widget 1.1.1 and have a look at users' reviews on Droid Informer. This installation package requires 509 KB on disk and it runs on Android devices 2.3.3 and higher.