The long-awaited Nintendo Switch version of Yooka-Laylee is being held back by issues with game engine Unity.

Developer Playtonic's latest blog update on the game blames the long wait so far on Unity needing to update to its latest version, 5.6, in order to solve the the engine's remaining issues.

Now 5.6 is released - but it has introduced new problems instead.

"Although [5.6] has now been released, it has unfortunately introduced other issues which we are working with Unity to resolve before we can submit to Nintendo and lock in our release timeline," Playtonic wrote.

"We understand the frustration that it's taken so long to get the game in your hands but we hope you understand that we're working as fast as we can and want the game to perform as well as it possibly can on Switch.

"Once these remaining issues are resolved we hope to finally be able to commit to and share a launch date. Thanks as ever for your patience and please bear with us - we are getting there!"

Yooka-Laylee was originally designed for release on Wii U, a console which Unity was one of the few major engines to support. But the Wii U died a slow death and Unity stopped supporting it. In time, Yooka-Laylee's Wii U version was dropped, and a Nintendo Switch version entered development instead. The Switch version supports plenty of engines Wii U did not - but by this point Yooka-Laylee was already built using Unity.

There appears to be an issue with Unity on Switch in general. Last week, fellow Kickstarter project Battle Chasers: Night War said it was similarly waiting on a new version of Unity before it could release.

There's a brief new snippet of Yooka-Laylee Switch gameplay footage viewable via the blog link above.