Drupal 5? Wow! I began my Drupal journey on the 4.6/4.7 'cusp' after working with J2EE & although I like Drupal because I can see the 'bigger picture' of the business logic being infused into the API, i.e. business problems solved = code as opposed to using something like Laravel & creating new untried, untested code all the time, I only really started liking coding with Drupal 8 as it's almost a complete rewrite from procedural to mostly OO.
The major problem over the years of fire-fighting various dubious installs of Drupal is people hack core and contrib modules making it impossible to maintain - if you use the APIs, grow modules & extend instead of hacking then it makes life a whole load easier - all I do to update my sites now is 'composer update --with-dependencies' (well, there's a few more lines to update the db if needed, export config from db to code, etc. but it's super-simple).
I hope you have applied a patch to protect against the latest security issue found, here's a link to an unofficial patch for 5:
The major problem over the years of fire-fighting various dubious installs of Drupal is people hack core and contrib modules making it impossible to maintain - if you use the APIs, grow modules & extend instead of hacking then it makes life a whole load easier - all I do to update my sites now is 'composer update --with-dependencies' (well, there's a few more lines to update the db if needed, export config from db to code, etc. but it's super-simple).
I hope you have applied a patch to protect against the latest security issue found, here's a link to an unofficial patch for 5:
https://www.drupal.org/files/issues/2018-03-28/sa-core-2018-...