As has been reported on multiple websites, the packaging for the upcoming Japanese budget version of Phantasy Star Portable 2 has revealed a possible expansion called Phantasy Star Portable 2 Infinity. Little is currently known about Infinity beyond the fact that it will let you import save data from Phantasy Star Portable 2. Further details may become available when the budget version is launched on August 26th.

Credit goes to NekoRul for bringing us this news. You can discuss this possible expansion in this forum thread.