This hook will set a number of posts that users must have to send new PMs. You can set the required number of posts, including if you would like to display this number in the message, and which user groups will be affected.
Step 1: Import the Hook file
Log in to your IP.Board Admin CP and visit the System tab -> Applications & Modules -> Manage Hooks page. In the 'Install a New Hook' section, browse to the XML file included with these instructions and click Open.
Step 2: Admin CP Setup
Still inside the Admin CP, visit the System tab -> Tools & Settings -> System Settings page, and click on the Hooks tab. There will be a section here entitled (SOS31) Posts Required to Send PMs v1.0.0. Click on this to adjust the settings for this hook, then click the Update Settings button.