We already have the next Japanese expansions sv4K Wild Force and sv5M Cyber Judge.
The sets will be released in Japan on June 26 and will feature 71 cards, not counting the secret cards. This expansion will feature the Paradox Pokémon: Ripplewater (Suicune) and Ferroverdor (Virizion). In this set, Flamariete (Entei), Electrorage (Raikou), Ferromole (Terrakion) and Ferrotesta (Cobalion) will debut.
These letters will reach the West through Temporal Forces.