Please read the upgrade notes corresponding to the version you are upgrading from.
See also :doc:`./backward_compatibility_notes`.
The manual mentions changes to project space. To perform the update, you need to compare the original files from vendor/codeigniter4/framework or from the ZIP archive and make changes.
Example, the original app/Config/App.php will be located in vendor/codeigniter4/framework/app/Config/App.php. Alternatively, replace it with a new file and add your previous lines.
Note
If you don't know what version of CodeIgniter you are currently running,
you can get it from :ref:`the Debug Toolbar <the-debug-toolbar>`,
or simply echo the constant \CodeIgniter\CodeIgniter::CI_VERSION.
.. toctree::
:titlesonly:
backward_compatibility_notes
upgrade_472
upgrade_471
upgrade_470
upgrade_465
upgrade_464
upgrade_463
upgrade_462
upgrade_461
upgrade_460
upgrade_458
upgrade_457
upgrade_456
upgrade_455
upgrade_454
upgrade_453
upgrade_452
upgrade_451
upgrade_450
upgrade_448
upgrade_447
upgrade_446
upgrade_445
upgrade_444
upgrade_443
upgrade_442
upgrade_441
upgrade_440
upgrade_438
upgrade_437
upgrade_436
upgrade_435
upgrade_434
upgrade_433
upgrade_432
upgrade_431
upgrade_430
upgrade_4212
upgrade_4211
upgrade_4210
upgrade_428
upgrade_427
upgrade_426
upgrade_425
upgrade_423
upgrade_422
upgrade_421
upgrade_420
upgrade_418
upgrade_417
upgrade_416
upgrade_415
upgrade_414
upgrade_413
upgrade_412
upgrade_410
upgrade_405
upgrade_404
upgrade_4xx