> Although BoringSSL is an open source project, it is not intended for general use, as OpenSSL is. We don't recommend that third parties depend upon it. Doing so is likely to be frustrating because there are no guarantees of API or ABI stability.

BearSSL is still beta-quality, s2n has not reached 1.0 (weekly releases are likely to break things), and BoringSSL has no guarantees of API or ABI stability.