SVN externals allow to include (nest) a remote SVN repository into another SVN repository. They are a great way to keep the latest code from another repository without having to do much.
One thing you will need to do is tell svn what revision of this remote SVN repository to load. To do that, do the following.
Command to find out what revision you’re svn external is pointing at;
svn propget svn:externals -R
This will output something like;
home/application - some-plugin -r100 https://svn.test.org/repos/test/some-plugin
Go to home/application directory;
Now change the revision number;
svn propset svn:externals 'some-plugin -r101 https://svn.test.org/repos/test/some-plugin'
Then commit to svn branch and you’re done.