Upgrade my Ubuntu 12.04.5 LTS 32 bit server from Traccar 3.7 to 3.13 server

Dear Sirs,
I want to upgrade Traccar 3.7 to Traccar 3.13 server.
My server is running Ubuntu 12.04.5 LTS (GNU/Linux 3.2.0-70-generic-pae i686) 32Bit with kernel 3.2.0-70-generic-pae #105-Ubuntu SMP if that matter.
The installed java is: java version "1.7.0_121"
OpenJDK Runtime Environment (IcedTea 2.6.8) (7u121-2.6.8-1ubuntu0.12.04.3)
OpenJDK Server VM (build 24.121-b00, mixed mode).

I tried to upgrade to Traccar 3.13 server but unsuccessfully.
So the questions are:

1. Is there any problem to install the latest traccar server to my server/software environment?
2. What is the preferred way to back up my configurations ( devices, users etc ) from my running traccar server to the new? Just to tell you that I used the build-in database.

Thanks and Best Regards,
Mike Kranidis

I would recommend you to follow official upgrade guide:

https://www.traccar.org/upgrading-traccar/

Dear Anton,
first of all I thank you for your reply.

I followed the instructions from your link and please see my comments:

1. Make a database backup ==>
   **I am not sure how to take a backup of the h2 database. Is there any how-to to follow ? **

2. Backup your config file (if modified) ==>
   If you means the file /opt/traccar/conf/traccar.xml then yes I did backup this

3. Remove old version of Traccar ==>
   ** I used the command: /opt/traccar/bin/traccar remove is it right?**

4. Install new version of Traccar ==>
   I can't because the new installation finished abnormally with error. Even when I tried to make a new installation to a new directory the result was the same...

5. Restore config file (if applicable) ==>
   Not performed this step due to error in (4)

6. Start Traccar service ==>
   Not performed this step due to error in (4)

Commands for installing and removing Traccar:

https://www.traccar.org/linux/

ok as your link suggested I did:
" 3.7 and earlier: sudo /opt/traccar/bin/traccar remove
Remove traccar directory (sudo rm -R /opt/traccar)"
for uninstall of the version 3.7 that I had installed and then:
Run traccar.run (sudo ./traccar.run) for the new installation. Not finished well though...
Then sudo /opt/traccar/bin/startDaemon.sh does not started the traccar server due to installation problem...

I will redo everything again and I will report back to you. Thanks

Dear Anton,
I redo everything from the start and now I have my server upgraded to 3.13 so I did something wrong last time... sorry ! ( you know I am "the old horse..." )
The new web environment uses very light / pal colors is there any adjustment that I can do, in order to get the old feeling?

Many thanks for your help.

Best Regards,
Mike Kranidis

You can change theme, but it would require JavaScript code changes.

OK thanks, then it is not for me. Good night Sir!