Ahead of the Apple Watchs 24 April launch, Apple has opened up the app submission process for the device to all developers.

Also available is Apples guide to preparing Apple Watch apps for submission. The app preview video used on the App Store must continue to use footage of the iOS app, rather than the Apple Watch version. Developers can upload up to five screenshots of the smartwatch app, though two of which will be initially visible in the carousel; and can add up to 100 characters of keywords, with terms like watch and app advised against, and Apple Watch outright banned.

The first details of official partnered apps for the device are also starting to emerge. The New York Times has revealed that it will deliver single-sentence stories written specifically for the small screen. Users can then use Apples Handoff function to see the full story on their iPhone or iPad, or tap save for later to add it to a reading list.

Meanwhile, Piper Jaffray analyst Gene Munster has forecast opening weekend sales of 1m units for the smartwatch, based on a 0.5 per cent attach rate of current iPhone users. Munster predicts 300,000 units will be sold in the first 24 hours. By the end of the year, he expects sale of 8m – equivalent to $4.4bn in revenues, around two per cent of Apples annual total – and 40-50m by the end of 2017.