Magento’s Q4 2021 update of 2.4.3-p1 and 2.3.7-p2 versions pre-release date is September 28, 2021, and its general availability would be from October 12, 2021.
Like always, Magento strives to strike the perfect balance between releasing product upgrades in the most simple, predictable manner with the most desired improvements and features for the merchants.
PHP 7.3 is about to reach its end of life in December 2021, hence it is advisable for you to update to PHP 7.4.
However, they’ve extended the security support for the Magento 2.3x release line for an additional three-month period (through April 2022).
The compatibility for PHP 7.4 has been initiated in May 2021. But still, if you’re still using Magento 2.3, we encourage all merchants to upgrade to PHP 7.4 for compliance reasons.
You must note that later 2.3x versions and Magento 2.3.7 will still be compatible with PHP 7.3, but Adobe will not release any fixes for them or test them.
Since Magento 2.4x already supports PHP 7.4, it’s recommended to adopt it as soon as possible.
See this DevBlog article for details about PHPUnit migration. Additional compatibility considerations are documented in the Magento 2.4 backward incompatibility DevDocs article.
Key Takeaway from the Release
While Adobe’s added support for PHP 7.4 in the 2.3.x release line will deliver PHP compatibility through the life of Magento 2.3, we at Rave digital still recommend you to analyze first and then prioritize your upgrade to Magento 2.4. Doing this will ensure long-term success for your eCommerce store with the latest, most secure version of Magento.