title: Validating Upgrade of PHP applications
body: <p>We have many php applications working on old php <strong>version 5</strong>.</p>
  <p>Now am working on to update the codebase from <strong>php 5 to php 8</strong>. To update codebase am using packages like phpcompatibility/php-compatibility, phpcsstandards/phpcsutils etc.</p>
  <p>After each application codebase update (to php 8) I will generate compatibility report (using phpcompatibility) to validate the update.</p>
  <p>But I want to be sure (that codebase will work on php 8) and not only depend on report (phpcompatibility).</p>
  <p>Hence, I <strong>decided to deploy applications on local servers</strong> (on php8, to check). <strong>But each application</strong> is giving me headaches. Each application <strong>ask for specific requirements</strong> (databases, users, files, classes). The php applciations were developed by other teams who have moved on (I dont have the environment in which they were developed).</p>
  <p>Is there any <strong>quick</strong> way to do it? Am thinking may be I can -
  1.go to production server
  2.create docker Image
  3. Open docker image locally and <strong>update php</strong> version(php 8)
  4. Deploy php application in this local docker image (php applciation codebase is now 8)
  5. If everything looks ok <strong>then update the</strong> production server version to php 8.</p>
  <p>Am not sure will this work, is there any better way?</p>