If phone number of contact in address book contains space like 1 800 1234567, Zoiper pro fails to dial.
Regular Zoiper (not pro) and old Zoiper lite dial such numbers without any problem. As result of this, impossible to use android phone address book. I have 600 entries in address book and it is impossible to replace spaces.by dash (-) like 1-800-1234567. The problem exists at least with US numbers that starts with 1 (11 digits format) or starts with +1 like +1-234-1234567(international format).
The problem exists on 3 different phones with Android 6 and Android 7