What is a Wiki Post?
The Discourse platform that the Fairphone Forum uses allows Moderators & Admins to mark a post as a ‘‘Wiki Post’’. A Wiki Post is a post that is editable by everyone on the forum with at least the Basic User level of access, and remains editable even after a Topic is closed.
Why Use Wiki Posts?
Wiki Posts are a useful way of allowing other community members to contribute to a solution and keep it updated, even after the Topic has been closed. We will only use Wiki Posts to mark Best Answers & Solutions. By having Wiki Posts the community can make adjustments or add additional information - just like you would on other Wiki
How to Identify a Wiki Post?
Very simple indeed.
Every time you see the following icon 
in the upper right corner of a post you will know you are looking at a Wiki Post and can contribute & tweak the solution if you spot something wrong or outdated, and indeed where you have an alternative solution that achieves the same overall result.
Find all wiki posts here.
How to Edit a Wiki Post?
Click the Wiki Post icon
When making edits to the post, make sure you pop a reference in to say you have edited the post and why. For example if you have added an additional solution you should put something like this above the additional information you are adding to the post [Edit: By @Chris_R - added additional solution].
If you are changing the solution that was already in place, you still need to make an edit reference, however you may wish to make this at the bottom of the post.