phpBB, free and open-source software that is highly customizable, powerful, and very easy to use. It is basically an Internet Forum package which is written in PHP scripting language. It simplifies various tasks for the user such as adding quality content to the website, form community, attract new people, and much more. It offers many other features like assigning permissions to forum members, set up any number of categories or forums, etc. All of these make phpBB a feature-rich application for forum running. phpBB 3.3 is the most recent and latest update.

Pros

• No Security Issues
• A very tradition forum look
• Too many choices available such as plugins, themes, etc
• Extensive Community
• Enormous Number of people are already using it
• It barely uses any CPU power and memory space