Pokémon Bank has at last been updated to let you transfer Pokémon into the series' latest games, Sun and Moon.
The app acts as a virtual cloud storage for your critters. Upload caught creatures into Bank from one game and you can download them into one of the series' later titles.
Bank, and accompanying app Poké Transporter used with older games, are supported by (deep breath): Pokémon Black/White and Black 2/White 2 on DS, Pokémon X and Y plus Omega Ruby and Alpha Sapphire on 3DS, and the 3DS eShop versions of Red, Blue and Yellow.
It's worth noting the journey to Sun and Moon is a one-way trip. Once sent forward, you can't transfer creatures back into a previous game. There's a full diagram below:
Also of note: Bank isn't free. The app carries an annual Ł4.49 subscription, but Bank as a whole just got a lot more useful. The app now tracks which Pokémon you have caught across all of your linked games in one central Pokédex.
It's an interesting move since the games themselves are moving towards their own, smaller pool of Pokémon for each region, especially as the overall number of creatures increases.
Subscribe to Pokémon Bank before October and you get the rare Z-Crystal Mewnium Z for Mew to use in Sun and Moon. You can read more about the various caveats of the update in our Pokémon Bank Sun and Moon update explainer.