title: Cannot find save handler 'memcached' - session startup failed
body: <p>I have my own simple hosted site on Fasthosts. I was offered to upgrade PHP from 7.0 to 7.3 but I am getting the following error:
  Warning: session_start(): Cannot find save handler 'memcached' - session startup failed in /home/xxx</p>
  
  <p>I have tried changing numerous ini settings, including reverting to 'files', all to no avail. It just fails on session_start(). The support staff just say there is no problem! I have now downgraded to 7.0 and it works fine.</p>
  
  <p>I did try 7.1 but received error:
  "Warning: Unknown: using touch command with binary protocol is not recommended with libmemcached versions below 1.0.18, please use ascii protocol or upgrade libmemcached in Unknown on line 0".</p>
  
  <p>I will stay with 7.0 but would like a fix as I also have a Charity website for the U3A and cannot risk that failing.</p>