Upgrade SVN

This procedure uses the SVN MultiSite Plus Upgrade procedure to upgrade both your SVN installation and those components of SVN MultiSite Plus that are bound to the specific version of SVN that you have installed. Again, this requires that your MultiSite deployment, including SVN servers, are offline during the time it takes to upgrade at each node. Please plan this procedure accordingly.

Before you start, ensure that you have the latest build of your version of SVN MultiSite Plus which contains the version of SVN to which you intend to upgrade.
Test the new version of SVN in a test environment before going into production with it.
Once you are ready to deploy the new version in your production environment, perform a synchronized stop. See Performing a Synchronized Stop of all nodes.

** Alert! ** Keep Updates Uniform
All nodes should be updated in the same way, using the same upgrade method. It is vital that SVN behaves in exactly the same way on all nodes. If it doesn't then it is possible that hard to detect quirks will result in repository data going out of sync.

Open a terminal window and login to the server.

Get the latest installer file and make sure it is executable:
```
chmod a+x svn-multisite-plus.sh
    
```

Run the installer:

    ./svn-multisite-plus.sh
Verifying archive integrity... All good.
Uncompressing WANdisco SVN MultiSite Plus.............
    ::   ::  ::     #     #   ##    ####  ######   #   #####   #####   #####
   :::: :::: :::    #     #  #  #  ##  ## #     #  #  #     # #     # #     #
  ::::::::::: :::   #  #  # #    # #    # #     #  #  #       #       #     #
 ::::::::::::: :::  # # # # #    # #    # #     #  #   #####  #       #     #
  ::::::::::: :::   # # # # #    # #    # #     #  #        # #       #     #
   :::: :::: :::    ##   ##  #  ## #    # #     #  #  #     # #     # #     #
    ::   ::  ::     #     #   ## # #    # ######   #   #####   #####   #####

Checking SVN

The installer will detect your current SVN installation and provide options for any possible upgrade.

Resume SVN MultiSite Plus. See Starting nodes.
Perform some tests at each node to confirm the update has completed successfully.

Downgrade SVN Binaries

It's possible to downgrade your installed version of Subversion without having to perform a complete reinstallation of SVN MultiSite. Here's how:

You'll need to interrupt SVN usage/replication. We start by disabling Apache to cut SVN repository access, then shutting down SVN MultiSite Plus.
```
/etc/init.d/httpd stop
/etc/init.d/svn-multisite-plus stop
```
Uninstall your current version of Subversion, for arguments sake let's say it's SVN 1.8:
```
yum remove subversion*
```
This will remove your current installation of Subversion. There will be some SVN-related files that form part of the MultiSite installation. We'll deal with these in the next steps.
Download the SVN MultiSite package that comes bundled with the earlier version of SVN. Install it to a temporary location using the non-interactive mode:
```
bash svn-multisite-plus.sh --noexec --keep --target /tmp/svn-multisite-plus-svn1.7
```
This method brings in the necessary files for update whilst making sure that the deployments settings and configuration are not lost during the downgrade.

Next, we'll use yum erase to remove files that are not flagged as 'configuration', then reinstall the earlier versions downloaded in the previous step:

yum -y erase svn-multisite-plus subversion subversion-debuginfo mod_dav_svn 
yum -y --nogpgcheck install rpm/* resources/svn/* resources/httpd/*

Restart Apache.
```
/etc/init.d/httpd start
```
Restart SVN MultiSite Plus.
```
/etc/init.d/svn-multisite-plus stop
```