hi, their site says "Mozilla Firefox 49 and above" are supported. so you can try to replicate this behaviour when you launch firefox in safe mode once to see if an addon is interfering here... Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems

firefox 52esr will only receive updates for security vulnerabilities until the end of august & no further compatibility fixes for third-party websites and services. you should seriously look into updating your outdated windows xp at this point!

PayPal is looking for Firefox 49.0 and later. https://www.paypal.com/us/smarthelp/article/how-do-i-check-and-update-my-web-browser-faq3893

No need for Firefox 52 ESR to be updated for this.

Firefox has supported TLS 1.2 by default since Firefox 27.0 Release (Feb 4, 2014) as per Bug#861266.

From Firefox 60 Release Notes:

On-by-default support for draft-23 of the TLS 1.3 specification

There are TLS settings prefs on the about:config page that specify the minimum and maximum TLS version.

• security.tls.version.min = 1
• security.tls.version.max = 4

1 means TLS 1.0 2 means TLS 1.1 3 means TLS 1.2 (default for max as of 27 to 59) 4 means TLS 1.3 (default for max as of Fx 60.0, though 59.0 did have support)

• http://kb.mozillazine.org/security.tls.version.*

Firefox 53.0 and later for Windows requires Windows 7, 8, 10. The only other way to run more current versions of Firefox on your old hardware is to perhaps dual boot with a light 32-bit Linux distro like Lubuntu or Xubuntu among other light 32-bit Linux distro options that still supports the ancient 32-bit CPU's.

See also:

• https://www.paypal.com/us/smarthelp/article/how-do-i-check-and-update-my-web-browser-faq3893
• https://www.ssllabs.com/ssltest/analyze.html?d=www.sandbox.paypal.com