The company I work at is in a high-growth phase and we are going to be expanding our global audience this coming year through various channels (SEO, performance marketing, sales, etc.). A 1-5% hit in potential customer traffic is not going to fly. Is my only option here to get off LetsEncrypt? A bit of a vent, but I would 100% had paid for a version of LetsEncrypt that supported their costs for the x-signature with I…
Android 6 is 2015. root and intermediates CA have a 10 and 5 year lifespan. I am afraid you might not be able to find something that work on old phones and new phones.
Even if you do find an older CA vendor that has an ancient CA and is willing to sign (you will be forced into an enterprise contract that will take months to negotiate), it's going to be retired anytime soon and break everywhere.
Last but not least. Old phones are stuck on old versions of SSL/TLS, they're not able to connect to recent websites irrelevant of the certificates. Your site is probably no exception and cut the old protocols a long time ago.