You asked and we listened. When we launched branch permissions for Git a couple of weeks ago, a lot of you have reached out to us and asked to add the same feature for SVN. We are launching it today.
Now you can restrict commit access to any branch (including trunk) in your SVN repository to allow only a certain group of people to commit to it. Everyone else will still be able to update, checkout and view contents of the restricted branch as usual, but they won’t be able to commit anything to it.
Branch permissions for both SVN and Git are available on all plans. You can enable them by going to Settings > Permissions inside your repository. You have to be an admin or owner in order to access that page.