LetsEncrypt ISRG Root X1's IdenTrust DST Root CA X3 cross-signing has come to an end. This means that any device/browser (including KaiOS devices) which doesn't yet trust the ISRG Root X1 will no longer trust any site with a LetsEncrypt certificate (which, by the way, includes kaiostech.com!). - Source: Reddit / 4 months ago
Do you know an article comparing KaiOS to other products?
Suggest a link to a post with product alternatives.