PiAware: Fine for 4+ yrs and now it's not

Upgrading from Wheezy to Jessie (or Stretch), and Piaware from whatever to ver 3.5.3 most likely will solve this problem.

One way to do this is a fresh install: Format mocroSD card, download and write latest Raspbian Stretch image, then install Piaware 3.5.5 and dump1090-fa add-on package.

Alternatively, try to upgrade existing software from Wheezy to Jessie, and Piaware from whatever version to 3.5.3. Following post tells how to do above upgrade.

I recommend reading the whole thread before attemting upgrade from wheezy to jessie, and to piaware 3.5.3.