When the 18.07 release was implemented, records were created in the new MASTPH table. The following labels were used for all numbers that were in your MASTER and MASTRL tables as of the date you received the release: 
 
Formerly stored as Conversion Label Conversion Seq#
Home Phone PHAREA and PHNUMB in MASTER HOME? 1
Cell Phone MTOPHN in MASTRL MOBILE? 2
Work/Employer Phone MTEPHN in MASTRL WORK? 3
Previous Phone MTPPHN in MASTRL PREVIOUS? 4
Fax FAXNO in MASTER FAX? 5
 
The label is intended to show where the number originally came from during the conversion process, and the question mark means the label is unconfirmed. For example, many members had their mobile phone numbers in the old “home phone” field.
 
These are not part of your CU’s set of configured labels, nor do they need to be added to your config, but you should give your MSRs and call center operators some instructions on how to confirm with members and adjust the labels appropriately to clean up your database over time.