The courts have made the first critical decision in the Epic vs Apple case, in part granting and denying Epic's request for a temporary restraining order.
Yvonne Gonzalez Rogers, US District Court Judge for the Northern District of California, has ruled that Apple is now restrained from blocking Epic Games from the Apple Developer Program on the basis of Fortnite subverting the 30% in-app purchase commission.
This decision includes Unreal Engine and has been made in part to protect other developers that use Epic's technology to power their games, according to the court document.
The ruling will come as a relief to various games firms, including Microsoft, which filed a statement of support for Epic earlier this week.
However, the court has not ruled in favour of Epic when it comes to Fortnite being blocked from the App Store, as this will be decided during later proceedings.
The temporary restraining order is effective immediately and will remain in place until an order has been issued on the motion for preliminary injunction. The hearing for this is scheduled for Monday, September 28.
Rogers agreed that Epic has made a preliminary showing of irreparable harm when it comes to Apple blocking its developer tools. It was also noted that these are handled by Epic's subsidiary Epic Games International, which holds separate developer program license agreements with Apple, and these have not been breached.
The court decided there was "potential significant damage" to both Unreal Engine and the games industry in general.
"Apple does not persuade that it will be harmed based on any restraint on removing the developer tools," she wrote. "The parties' dispute is easily cabined on the antitrust allegations with respect to the App Store. It need not go father.
"Apple has chosen to act severely, and by doing so, has impacted non-parties, and a third-party developer ecosystem. In this regard, the equities do weigh against Apple."
She later added: "Epic Games and Apple are at liberty to litigate against each other, but their dispute should not create havoc to bystanders."
The judge said Epic had not sufficiently demonstrated that it should succeed in the overall case -- "especially in the antitrust context" -- although she agrees that "serious questions do exist," especially around Apple's 30% fee.
Epic has attempted to make the case that it should be allowed to use Apple's platform but not have to pay this fee, instead offering direct payment options to Fortnite users.
On this, Rogers wrote: "While the Court anticipates experts will opine that Apple's 30% take is anti-competitive, the Court doubts that an expert would suggest a 0% alternative. Not even Epic Games gives away its products for free."
The judge also ruled that Epic "has not yet demonstrated irreparable harm" as the current situation "appears of its own making."
She notes the company has already admitted it could deactivate the hotfix that introduced direct payments to Fortnite, and the fact it would prefer not to litigate while still maintaining its agreements with Apple "does not mean that 'irreparable harm' exists."
Rogers observed that this feud between Epic and Apple has been "brewing for some time" but adds: "It is not clear why now became so urgent."
She recognised that the dispute was triggered by Epic's "calculated decision to breach it's allegedly illegal agreements with Apple" and its "pre-planned, and blistering, marketing campaign" against the iPhone firm.
This campaign has resulted in the court being presented with "numerous internet postings and comments" from Fortnite players. But Rogers says these should have no bearing on the case.
"The showing is not sufficient to conclude that these considerations outweigh the general public interest in requiring private parties to adhere to their contractual agreements or in resolving business disputes through normal, albeit expedited, proceedings."
Last week, it was reported that Rogers has previously presided over a similar case, and ruled in favour of Apple.
Epic Games is currently involved in a similar legal dispute with Google.