To make sure it’s ready for a day its CEO called “one of the biggest TV moments of the year,” Sling TV has pushed back the launch of HBO on its service. Sling originally was scheduled to debut the premium channel on its service Wednesday morning, less than 24 hours after the launch of HBO Now, but it will debut instead on Saturday, April 11.  

The premium cable channel, which is available as a $15 add-on to Sling's basic service, still will be ready in time for the return of "Game of Thrones" this Sunday. A Sling representative said the delay will enable Sling to make a number of upgrades to its service, including changes designed to improve the service’s performance during periods of high viewership. Sling declined to give specifics on the changes, calling them proprietary. The service also will add parental controls and updates to the mini guide that will make it easier for users to find Sling content through devices like Roku and Xbox One. 

While the changes have been in the works for weeks, they come on the heels of the service's first high-profile slip-up since it debuted at the Consumer Electronics Show in Las Vegas in January. Over the weekend, customers complained that the service struggled during the first game of the Final Four. Sling TV CEO Roger Lynch told Wired on Monday that the issues affected fewer than 1,000 consumers, but that didn’t stop an avalanche of negative coverage of the service, much of it asking whether services like Sling are ready to deliver to mass audiences.

It could be argued that no service is ready for prime time because Internet infrastructure is not ready for streaming video on a truly mass scale. The upgrades Sling has made may not be enough to ensure smooth sailing on Sunday night, either; subpar streaming video experiences can be caused by a host of things that providers like Sling have no control over, including congested Internet connections, poor routers or bad delivery from third parties.

“Game of Thrones,” the most-pirated television show in the world, has a history of putting unusual levels of strain on the Internet. Last year, so many people signed in to HBO Go to watch the premiere of Season 4 that that service crashed, a move that led to HBO teaming up with MLB Advanced Media to help build HBO Now. HBO appears to be steeling itself for a challenging weekend too – it has already set up a page for customers who may be wondering why its service is pausing or buffering.

Though it’s tempting to frame Sunday performance as a make-or-break moment for the Sling service, there are other factors in place that will limit its near-term growth. Earlier this month, reports surfaced that Sling had agreed to caps that allow content partners to pull their content off the service if its subscriber base gets too big.