Deregulation Act 2015
The Deregulation Act 2015 means that there are 2 different regimes in operation for the serving of s21 notices under an Assured Shorthold Tenancy. Which one is actually used depends on whether the AST commenced before or after the 1st October 2015. An overview of the two regimes can be read here.
The Act also provides new protections for tenants under what has become known as retaliatory evictions, more of which can be read here.