Hi,
Your question is related to your hosting, so probably the best place to get a help is there.
Just notice you that PHP 5.5 is far from the latest version of PHP. Currently, it is php7 the latest one which is incredibly fast compared to 5.5 or 5.6.
Anyway, you can try to clean cache of your site (in hosting if there is something like that) and in your browser too.
WordPress works well with php7, so there is no any issue with older php like 5.5 or 5.6. I think if you use quality plugin or theme, the same applies there.
Many thanks for your feedback Peter. Most grateful. I did initially try to sort this matter out with my hosting company, Site5. They suggested ensuing that all my plugins and themes were up to date which I did. My WP version is the latest version too. Still got the white screen though when I upgrade to version 5.5 which, incidentally, is the latest version that Site5 offers. Perhaps I should try a different theme? Is Site5 sufficiently reputable?
Kind regards, Richard
Yes Richard, that is the way how to troubleshoot/debug things. Change theme, if that does not help, then turn off plugins one by one that you can determine what cause the issue.
Even if all your plugin are updated to the latest version, some plugin can release the latest version two years ago 🙂 but the most chance is, that it cause your theme.
I am probably not the right person who can tell you if site5 is sufficiently reputable hosting, bc. for me any hosting who use cpanel and does not offer the latest php – now php7 is a waste of money 🙂 also I am not a fan of a classic shared hosting.