boincstats + Chrome 49 (last for XP) + Windows XP SP3
When I access this website: ERR_SSL_VERSION_OR_CIPHER_MISMATCH

Firefox 52.1.1 esr in XP work ok. Use TLS1.2, TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256 0xc02b
Chrome 49 for W7 work ok. Use TLS1.2, TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256 0xc02b

Chrome 49 for XP not work with boincstats.com. Chrome 49 for XP offers TLS1.2 TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 0xc02f, but does not offer TLS1.2 TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256 0xc02b.

To view encryption subtypes: https://www.ssllabs.com/ssltest/clients.html

Chrome is my favorite browser for speed and I know that for webs that do not work like this, Firefox can be an alternative.
This leaves out all XP users with Chrome 49.
Why does boincstats.com not support TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 0xc02f if it is also encrypted TLS1.2?

https://support.cloudflare.com/hc/en-us/articles/214770928-Legacy-Browser-Support
It seems to be due to the root trust certificate of boincstats that is not appropriate. It does not support XP.
As a suggestion, I invite you to change the certificate to allow XP users without lowering security, as do all web pages of banks that support XP users with the highest security.

This site is using the Cloudflare free plan which does not allow lowering the security settings to accommodate outdated Operating Systems or applications. This requires the business plan which costs $200 per month. So if you are willing to pay for that I can change the security settings.