doc: Add recommendations for manual updates (#4557)

docs/en/admins/04_Updating.md

@@ -12,7 +12,13 @@ If you enabled web updates from your installation (see footnote 2 in [installati
 
 This will check for and apply a new Stable version, if available.
 
-## Updating Using git
+## Updating manually
+
+There are two options to update manually: with git (recommended if you’ve installed FreshRSS this way), or from a Zip archive.
+
+In both cases, **it is highly recommended to update version by version.** For instance, if you are running FreshRSS 1.17.0, you should update to version 1.18.1 (i.e. the latest of the branch 1.18.x) before updating to 1.19.2. After each update, check that FreshRSS is still running correctly. If it’s not, it will help to understand what is broken.
+
+### Using git
 
 If you installed FreshRSS using git, you can update, change branches, or switch to a specific version from the command line.
 
@@ -25,6 +31,6 @@ Generally, the update procedure via git works as follows:
 5. Pull the new version.
 6. Re-set group read (and write, if you wish) permissions on all files in `.`, and group write permissions on `./data/`.
 
-## Updating from a Zip Archive
+### From a Zip Archive
 
 Updating to a new version from a zip archive is always an option. Begin by unzipping the archive into your FreshRSS directory, overwriting old files, and finally re-set group read (and write, if you wish) permissions on all files in `.` and group write permissions on `./data/`.

docs/en/admins/07_LinuxUpdate.md

@@ -4,6 +4,8 @@ This tutorial demonstrates commands for updating FreshRSS. It assumes that your
 
 **Note that FreshRSS contains a built-in update system.** It’s easier to use if you don’t understand the commands that follow. It’s available through the web interface of your FreshRSS installation, Administration → Update.
 
+Please read the general advices from “[Backing Up and Updating FreshRSS](04_Updating.md)” before applying any command from this guide.
+
 ## Pausing automatic feed updates
 
 If [Automatic Feed Updating](08_FeedUpdates.md) has been configured, temporarily suspend the automatic feed updates during the upgrade process.
@@ -92,7 +94,7 @@ If your local user doesn’t have write access to the FreshRSS folder, use a sud
 	chown -R :www-data . && chmod -R g+r . && chmod -R g+w ./data/
 	```
 
-6. Clean up the FreshRSS directory by deleting the downloaded zip, the file forcing the setup wizard and the temporary directory
+6. Clean up the FreshRSS directory by deleting the downloaded zip and the temporary directory
 	```sh
 	rm -f freshrss.zip
 	rm -rf FreshRSS-*/