Potential Tenant has kept out-of-state DL for 4 yrs

[Lu Carter]

I am screening a woman and her fiance (mid 40's) who have lived in TX for 4 years.  So far the information about landlord history and income is normal.  On their applications I ask for drivers license number and state and they have both listed a license from a former state.  Their rental and employment history shows them in Texas since 2011 and there is no information about them continuing to do business in their former state. Their current out-of-state licenses will expire within the next year. Is this flag of any sort?  I believe Texas does require new residents to obtain a Texas drivers license.