iPad mini 3 and Older
While the iPad mini fills a relatively niche market, they are very popular with certain segments of users. Unfortunately, only the iPad mini 4 and rebranded iPad mini (5th generation) will be compatible with iOS 13 – or, well, its iPadOS version. The iPad mini 3 and any earlier models won’t work. The mini 3 came out in fall 2014, for reference. You might be noticing a pattern here with cutoff dates.