Solved. Android. Existing package name only contains letters and does contain a dot ...

I was unable to publish updated version of my apk to the Play Store because the Developer Console complains that package name of the APK is wrong. "Existing package name only contains letters and does contain a dot, so the only reason for rejecting it that I can think of is package name starting with the upper-case letter. It does match the previously used package name."
     note: the apk has the same package name as previous version."

Solution: = just use Developer Console with  new  design.
Old one has the mentioned bug.

Hope you will save time I spent to figure out why it is happens.

Enjoy!