Epic Games made history at last year's Game Developers Conference when it opened its Unreal Engine 4 up to all via a monthly subscription model. At this year's conference, the company is doing away with monthly licensing fees and making its popular engine free for all to use.

In exchange for use of the engine, Epic Games will earn a five percent royalty on gross revenue after the first $3,000 per product, per quarter should a developer monetize a game or application built using Unreal Engine 4.

The change is effective immediately. Epic will be issuing a pro-rated refund to current subscribers for their most recent month's payment. What's more, anyone that has ever paid for a subscription will receive a $30 credit that can be used in the Unreal Engine Marketplace.

Up to this point, Unreal Engine 4 set developers back $19 per month.

Just to reiterate, we're talking about the full version of Unreal Engine 4, not some watered-down trial version. It includes all of the C++ source code and tools that Epic uses to build its own games. The engine also includes game templates, content samples and tutorials to help newcomers get acclimated to using it.

Epic also released a teaser trailer of sorts that showcases clips from multiple games built using its latest engine including Batman: Arkham Knight, DMC: Definitive Edition and Hellblade.