I have a 13” Mid 2013 MacBook Air 1.7 GHz i7 with 8GB. I replaced it with a 2015 MacBook Air 1.6 GHz i5 8GB RAM logic board, it worked for the most part. The guest ID never shuts off when shutdown was activated. Also had the “not found” icon of OS folder appear on first few attempts of boot. The replacement was in error since I ordered a 1.7 GHz i7 8 GB unit but not until I did About This Mac to check memory amount did I realize I was sold and installed a 2015 i5 1.6 GHz logic board.