We have a magento1 store and earlier it was being managed by someone else. We did scanned our website for security patches and scan result shows some patches are installed , some are not and some has unknown status. We do not have applied.patches.list file so we don't know which patches were installed earlier. Magento version is 126.96.36.199 How do we proceed in this scenario ? Any help will be appreciated
Use magereport.com to scan your site. They will tell you what patches are installed and what patches still need to be installed
Other option If you use any type of version control, look back at your project history and see if you find the patches there.
Also, you can try applying the patch (on a staging environment) and see if the server throws an error that it cannot apply patch, which might mean that it was patched already.
Finally, each patch file shows exactly what's being patched, you can just open any of the files listed in the patch and check if the patched code is in there.