Refresh Update FAQ and add explanation about why a release could be missing from Update Assistant

faq/upgrade.md

@@ -1,42 +1,42 @@
 ---
-title: Upgrade FAQ
+title: Update FAQ
 showOnHomepage: true
+aliases:
+    - /8/faq/upgrade
 ---
 
-# Upgrade FAQ
+# Update FAQ
 
-- [After upgrading, I lost access to some Back-Office pages](#restore-access-to-back-office-page)
-- [Upgrade fails with Error message JqXHR](#upgrade-fails-with-error-message-jqxhr)
+- [The newer version of PrestaShop is not shown on Update Assistant](#the-newer-version-of-prestashop-is-not-shown-on-update-assistant)
+- [The version of PrestaShop does not match the one stored in database](#the-version-of-prestashop-does-not-match-the-one-stored-in-database)
+- [Restore access to Back Office Page](#restore-access-to-back-office-page)
 
+## The newer version of PrestaShop is not shown on Update Assistant
 
-## Restore access to Back Office Page
-
-**Q:** After upgrading my PrestaShop to a new version, I lost access to some Back-Office pages. How can I fix it?
+**Q:** I've seen a new version of PrestaShop has been released, but Update Assistant keeps saying my store is up-to-date.
 
-**A:** It is likely that some SQL configuration is not correct.
+**A:** Several reasons may lead to the new version not being suggested:
+* It is not flagged for update yet. This can happen if the module is not ready or testing is ongoing.
+* The PHP version running the store does not match the required range. It will happen if PHP is either **too low** or **too high**. Ensure the [system requirements][system-requirements] are fullfiled.
 
-First, identify what is the `slug` of the Back Office pages. You can find them into the SQL table `ps_authorization_role`. This will tell you the SQL identifier for these pages.
-
-Second, identify the _Role_ of the User you use to browse the Back Office.
+## The version of PrestaShop does not match the one stored in database
 
-Third, check whether the table `ps_access` grants access to the Back Office pages, using the identifier of the role and the identifiers of the Back Office pages. There must be a record for the role and the page. If there is no such record, create it to grant access.
+**Q:** Update cannot start because the error "The version of PrestaShop stored in database does not match the running code. Your database structure may not be up-to-date and/or the value of PS_VERSION_DB needs to be updated in the configuration table." is displayed.
 
-## Upgrade fails with Error message JqXHR
+**A:** In PrestaShop, `PS_VERSION_DB` is a constant that holds the current version number of your PrestaShop database schema. The main purpose of `PS_VERSION_DB` is to keep track of the database schema's version history. When you update a shop, the database schema is modified to match the structure of the new version (e.g. add or remove tables, columns, or relationships). 
 
-If during upgrade process, it fails with the error message:
+Before updating PrestaShop, the update module relies on this constant to ensure that the current version matches the database schema. If the values don't match, it would be a sign of potential issues with the database structure or data which could lead to unforeseen consequences during the update process.
 
-```
-[Ajax/Server operation [...]] textStatus: "Error" errorThrown: "" JqXHR: "",
-```
+## Restore access to Back Office Page
 
-This error message indicates something went wrong on server side.
+**Q:** After updating my PrestaShop to a new version, I lost access to some Back-Office pages. How can I fix it?
 
-In order to find out what exactly went wrong, you need to check the upgrade process logs that are located into the folder `{Prestashop_Folder}/{Admin_folder}/autoupgrade/tmp/`
+**A:** It is likely that some SQL configuration is not correct.
 
-## The version of PrestaShop does not match the one stored in database
+First, identify what is the `slug` of the Back Office pages. You can find them into the SQL table `ps_authorization_role`. This will tell you the SQL identifier for these pages.
 
-**Q:** Upgrade cannot start because the error "The version of PrestaShop stored in database does not match the running code. Your database structure may not be up-to-date and/or the value of PS_VERSION_DB needs to be updated in the configuration table." is displayed.
+Second, identify the _Role_ of the User you use to browse the Back Office.
 
-**A:** In PrestaShop, `PS_VERSION_DB` is a constant that holds the current version number of your PrestaShop database schema. The main purpose of `PS_VERSION_DB` is to keep track of the database schema's version history. When you upgrade a shop, the database schema is modified to match the structure of the new version (e.g. add or remove tables, columns, or relationships). 
+Third, check whether the table `ps_access` grants access to the Back Office pages, using the identifier of the role and the identifiers of the Back Office pages. There must be a record for the role and the page. If there is no such record, create it to grant access.
 
-Before upgrading PrestaShop, the upgrade module relies on this constant to ensure that the current version matches the database schema. If the values don't match, it would be a sign of potential issues with the database structure or data which could lead to unforeseen consequences during the upgrade process.
+[system-requirements]: {{< relref "/8/basics/installation/system-requirements#php-compatibility-chart" >}}