Firefox updated its own extension framework from version 57, breaking most extensions and addons:
This is obviously no an addon's fault. All the 1.x releases of SAML-tracer are compatible with this new framework, but then they won't work with older versions of Firefox that don't include it. The other way around, older versions of SAML-tracer don't work with Firefox 57 and later.
As such, if you want to keep using Firefox 52.x, you'll need to stick to SAML-tracer 0.4. If you want to use the latest version of SAML-tracer, though, you'll need to upgrade Firefox to at least version 57.
Finally, SAML-tracer does not automatically update itself. This is a feature you have enabled in Firefox. If you don't want your addons to update automatically, then you need to disable this feature.