I have Gen #1 iPhone SE. I have a battery (new from iFixit in 2018-new
The battery is still in the original shipping envelope and has never been used or even opened up. My iPhone SE (Gen 1) is now showing signs of battery deterioration as it is not holding a charge too long. I wanted to change it but I am now concerned that the battery I have (new) is perhaps no longer any good? I asked iFxit but they cannot provide guidance and suggested I try the forum.