I have an old company provided phone (Samsung Galaxy S5) just sitting in my desk that has not been used in over a year after my company issued me a new iPhone.

My personal phone's speaker is giving me problems and temporarily cuts in and out. I dont have the funds for a new phone at the moment, payday is 2 weeks away.

If I put my personal SIM card in my old work phone, will my employer be able to find out I am using my old work phone as a personal phone? Would they be able to see any sites I visit or see what apps are installed?