system.tag.storeTagHistory() is depreciated from Ignition 80 docs?

Is there any specific reason for depreciating system.tag.storeTagHistory(). Any alternatives for this function.

The deprecation was basically a mistake. It’s not going to be removed (basically none of our “deprecated” functions ever are, for backwards compatibility) - consider it safe to use.

Thank you Paul for spontaneous response and confirming this.

So, in one of the next 8.1 release, this function will come back in help documentation and script autocompletion ?

Yes, most likely the original function will be returned to regular status.