EA announced that The Sims 4 will no longer be supporting 32-bit PCs and non-metal Mac OS machines by June 2019. Players will still be able to play the game thanks to an upcoming Legacy Edition.
The Legacy Edition has a tentative release planned for the same month that the support for older machines. This edition will transfer saved game files, but it won't receive future updates or bug fixes. It also won't support game or stuff packs that have released after February 26. You can read EA's full statement here.