HI Christophe,

I checked with R&D and they indicated you are correct about copying the folders:

In this case you must copy the entire folder C:\Program Files\Astea Publisher 15.0 from one server to another as they must be the same so the client will get updates from both servers with same manifest.

Please backup the folder C:\Program Files\Astea Publisher 15.0 on the second publisher server and copy the folder C:\Program Files\Astea Publisher 15.0 from the first publisher server to the second publisher server.

Otherwise, there may be issues getting updates down to the browsers for example.

Hi Christophe, the same logic applies if you have the Mobile Edge application installed on multiple load-balanced servers, details on how to do that are at the end of the Upgrade Installation Guide for Mobile Edge:

Synchronizing a Load-Balanced Environment

If you have the Alliance Mobile Edge application installed in a load-balanced 
environment, then there are two more additional steps you must perform after 
the installation process has been completed: 
1. You must synchronize the File Manifest files across each of the servers so 
that the time stamps are identical.
2. If you are using the Mobile Customizer application (or plan to do so in 
the near future), you must synchronize the Machine Keys on each server 
in the IIS Web Farm.

6.1 Synchronizing the File Manifest Files
When you login to the mobile application we check the Date Modified value on the 
file manifest that is affiliated with the particular operating system (this is different 
for iOS, Android and Windows). If the date modified value of this file on the mobile 
server is different than the last time the technician logged in, our application will 
automatically download the updated client files.
If you have the same file manifest on each of two/more load balanced servers 
BUT THE TIMESTAMPS ARE DIFFERENT on these files, then every time the 
technician logs in and gets directed to a different server our application thinks it 
has to download the files all over again. In order to synchronize the File Manifests 
you will need to do a copy/paste of the following three files from one mobile server 
to each of the other servers in your load-balanced environment:

\Program Files\Alliance Mobile Edge\AsteaMobileEdge\AndroidFileManifest.xml
\Program Files\Alliance Mobile Edge\AsteaMobileEdge\iOSFileManifest.xml
\Program Files\Alliance Mobile Edge\AsteaMobileEdge\WpFileManifest.xml

1. Open up File Explorer on the first mobile server and go to the \Program 
Files\Alliance Mobile Edge\AsteaMobileEdge folder.
2. Select each of the three files specified above (hold down the CTRL key 
while clicking on each one).
3. Right-click the mouse and select Copy (or do a CTRL-C):
4. Switch to one of the other load balanced mobile servers.
5. Open File Explorer and go to the \Program Files\Alliance Mobile 
Edge\AsteaMobileEdge folder.
6. Right-click the mouse and select Paste (or do a CTRL-V) to paste the 
files onto this server.
7. After you do the paste, do a quick comparison between the Date Modified
values on these files on each of the servers to confirm that they are now 
showing the same date/time stamp as they are on the server you copied 
them from.
8. Repeat this Paste process on each of the other load balanced mobile 
servers in your environment (and confirm that the Date Modified time 
stamp is the same).