Suggested by Patrik Müller – Needs Votes
Our customers keep expressing the wish that when entering telephone numbers, an automatic check should be carried out to determine whether a number is correct and corresponds to the country-specific format.
It should be possible to setup several telephone number formats per country/region, as has already been done with the VAT numbers.
If a telephone number is then entered (e.g. on a contact), it should be checked whether it is a valid number. It should be prevented that invalid numbers can be inserted.
In this way, all telephone numbers in the "address base" would appear uniform and incorrect entries would be reduced.
We should probably orientate on the E.164 standard, which defines a general format for international telephone numbers.