PA requires you to have residency in the state to keep your license. That is for renewals and I had basically the same message.
Also, since the state taxes on domicile they could argue that you owe state taxes by maintaining your license.
It is one of the items that could be used to prove domicile, so if you have it isn't a guarantee that you have domicile, but that is something you will need to weigh up for yourself.
According the PennDot:
Act 152 of 2002 prohibits PennDOT from issuing or renewing driver license products for any
person who is not a resident of the Commonwealth. Without a Pennsylvania address, no driver’s
license or photo identification card may be processed by PennDOT. This requirement is effective
April 6, 2003.
Q: Are there any exemptions from the requirement to have a Pennsylvania address?
A: Yes, if your workplace is located out of state and you are employed by one of the
following, you may qualify:
• U.S. Armed Forces
• Federal Government
• Pennsylvania Government
Q: I am going to school out of state. Would I qualify for an exemption?
A: No, Pennsylvania law does not exempt students from the residency requirement.
If they don't exempt students they certainly won't be exempting people who move overseas. It is depressing though.