How to upgrade PHP 8.0 to 8.1 and symfony 5.2 to 5.4

Upgrade PHP 8.0 to 8.1:

PHP 8.1 comes with several new features and improvements. Here are some of the
key features:

1. Fibers: PHP 8.1 introduces fibers, which are a lightweight alternative to
   threads. Fibers allow you to create cooperative multitasking applications
   in PHP, making it easier to write high-performance, non-blocking code.
2. Union Types: Union types allow you to specify that a variable can have
   one of several possible types. This makes your code more flexible and
   allows you to write more expressive type hints.
3. Read-only properties: With PHP 8.1, you can declare class properties
   read-only. Once a read-only property is set, it cannot be changed. This
   helps you write more secure and reliable code.
4. New string functions: PHP 8.1 introduces several new string functions,
   including str_contains(), str_starts_with(), and str_ends_with(). These
   functions make it easier to work with strings in PHP.
5. New array functions: PHP 8.1 also includes several new array functions,
   such as array_is_list(), which checks if an array is a list, and
   array_first_key(), which returns the first key of an array.
6. Improved error handling: PHP 8.1 includes several improvements to error
   handling, including better error messages and more informative stack
   traces.
7. Improved type inference: PHP 8.1 includes improved type inference,
   which makes it easier to write type-safe code.
8. Performance improvements: PHP 8.1 includes several performance
   improvements, including faster JIT compilation and better memory
   management.

Deprecated in PHP 8.1:

· Passing null to non-nullable internal function parameters are deprecated

· Return types in PHP built-in class methods and deprecation notices

· Serializable interface deprecated

· Implicit incompatible float to int conversion is deprecated

· mhash*() functions (hash extension) are deprecated

· mysqli::get_client_info method and mysqli_get_client_info($param) is deprecated

· date_sunrise, date_sunset functions and related INI settings are deprecated

· strptime function is deprecated

· strftime and gmstrftime functions are deprecated

· filter.default and filter.default_options INI settings are deprecated

· PDO::FETCH_SERIALIZE is deprecated

· auto_detect_line_endings INI directive is deprecated

· MySQLi: mysqli_driver->driver_version property is deprecated

Steps to upgrade PHP8.0 to PHP8.1:

Upgrading from PHP 8.0 to 8.1 will depend on the operating system and package
manager you are using. Here are the general steps to Upgrade PHP 8.0 to 8.1:

1. Check the current PHP version installed on your system by running the
   following command:

php -v

2. Update the package manager to ensure that you have the latest packages available:

sudo apt update

3. Add the Ondřej Surý repository to your package manager, as this repository
   provides the latest PHP packages:

sudo add-apt-repository ppa:ondrej/php

4. Update the package manager again:

sudo apt update

5. Install PHP 8.1 by running the following command:

sudo apt install php8.1

6. Restart any relevant services that use PHP to ensure that they are using the new
   version. For example, if you’re using Apache, restart it by running the following
   command:

sudo systemctl restart apache2

Note that the exact commands and steps may differ depending on your operating
system and package manager. It is always a good idea to back up your files and
configurations before performing any major updates or upgrades.

Upgrade Symfony 5.2 to 5.4:

Symfony 5.4 comes with several new features and improvements. Here are some of
the key features:

1. Improved PHP 8 support: Symfony 5.4 includes improved support for
   PHP 8, including support for the new union types feature and more
   informative error messages.
2. Improved security: Symfony 5.4 includes several security improvements,
   including better protection against cross-site scripting (XSS) attacks and
   stricter password hashing algorithms.
3. Improved cache layer: Symfony 5.4 includes several improvements to the
   cache layer, including better support for PSR-16 cache interfaces and a
   new cache pool adapter that can use the Symfony cache system as a cache
   backend.
4. Improved routing: Symfony 5.4 includes several improvements to the
   routing component, including better support for route requirements and
   the ability to generate URL fragments.
5. Improved console component: Symfony 5.4 includes several
   improvements to the console component, including support for colored
   output and improved error handling.
6. Improved translation component: Symfony 5.4 includes several
   improvements to the translation component, including support for
   pluralization rules and a new way to handle fallback translations.
7. Improved messenger component: Symfony 5.4 includes several
   improvements to the messenger component, including better support for
   message tracing and a new retry strategy.
8. Improved workflow component: Symfony 5.4 includes several
   improvements to the workflow component, including better support for
   custom state machines and the ability to define multiple workflows in a
   single file.

These are just a few of the many new features and improvements in Symfony 5.4.
Upgrading to Symfony 5.4 can help you write more secure, reliable, and performant
code.

Deprecations in symfony5.4:

Symfony 5.4 deprecates several features from previous versions. Here are some of
the major deprecations in Symfony 5.4:

1. Symfony 5.4 deprecates several methods and classes that were already
   marked as deprecated in previous versions. You should update your code
   to use the new recommended replacements for these deprecated features.
2. Symfony 5.4 deprecates the support for several PHP versions that are now
   end-of-life or soon to be end-of-life, including PHP 7.2 and 7.3. You
   should update your code to run on a supported version of PHP.
3. Symfony 5.4 deprecates the use of the “public” access modifier for
   properties in services. You should use the “private” or “protected” access
   modifier instead.
4. Symfony 5.4 deprecates the use of the “@autoconfigure” tag in service
   definitions. You should use the “@autoconfigure(true)” or
   “@autoconfigure(false)” tag instead.
5. Symfony 5.4 deprecates the use of the “session.storage” service in favor of
   the “session.factory” service. You should update your code to use the new
   service instead.
6. Symfony 5.4 deprecates the use of the “@deprecated” annotation for
   deprecating code. You should use the
   “@Symfony\Component\Deprecation\Deprecation” annotation instead.

Steps to upgrade Symfony 5.2 to Symfony 5.4:

We need to update the componer.json file and run the command composer update.
While updating it to the latest version we need to fix the code in the Symfony spark

bundle.Upgrading Symfony from version 5.2 to 5.4 involves several steps. Here are
the general steps:

1. Update your project’s composer.json file to require the new version of
   Symfony:

“require”: {

“php”: “>=7.4.0”,

“symfony/framework-bundle”: “5.4.*”,

// Other dependencies

},

2. Run composer update to update your project’s dependencies:

composer update

3. Update your application code to account for any changes or deprecations in
   Symfony 5.4. You can use the Symfony upgrade tool to help you with this step:

composer require symfony/upgrade-fixer –dev

vendor/bin/upgrade-fixer fix

4. Update your configuration files to account for any changes or deprecations in
   Symfony 5.4. The Symfony upgrade tool can also help you with this step:

composer require symfony/config symfony/yaml –dev

vendor/bin/console config:dump-reference framework

This will generate a reference configuration file that you can use as a guide for
updating your configuration files.

5. Run your application’s test suite to ensure that everything is working as expected.