Complex sentence: The regulator has therefore decided that new phone numbers must be 8 digits long including the extension, in order to fulfill this requirement, operators have to shorten a customer's phone number to 3-6 digits, to allow 2-5 digit extensions.
Split into simpler sentences: The regulator has therefore decided that new phone numbers must be 8 digits long including the extension. In order to fulfill this requirement, operators have to shorten a customer's phone number to 3-6 digits, to allow 2-5 digit extensions.