One major change with the introduction of Windows 10 was that Microsoft started to release a new version of Windows 10 twice per year, and with Microsoft's "modern lifecycle policy" a newly released Windows 10 version starts a "grace period" for the previous version with regard to support unlike previous Windows products which received only infrequent updates via service packs, and support was governed by the "fixed lifecycle policy". With this new policy Home and Pro versions of Windows 10 will be provided with security and feature updates (so called "mainstream support") for up to 18 months after release, "enterprise" and education versions for 24 months. To give an example: support for Windows 10 Home/Pro version 1703 (which was released in April 2017) will be stopped by Microsoft in October 2018, and support for versions 1507 and 1511 (released in 2015) officially ended in 2017. Microsoft announced that it would give "extended support" (security but not feature updates) for at least one "semi-annual channel" (SAC) Windows 10 version until October 14, 2025.