Thankfully, Yoast and others, including ourslves, are pushing for WordPress sites to not only have the latest version of WordPress, but also the latest version of Plugins, and the latest version of PHP. (PHP is the computer programming language on which WordPress is built).
PHP has been around for many years, and has, like other software, been updated to be more efficient, more secure, and take advantage of later processing technology over time.
The latest version of PHP is 7.1, which was release on 1 Dev 2016. Hosting companies can be forgiven for not having full support for this version for a while, but there is no excuse for not offering and providing V7.0 which can out in 3 Dec 2015.
Unfortunatly many sites, possible over a million, are still running versions of PHP which are so old, they can not longer be supported. This leaves them with performance issues, incompaitble with many of the latest plugins and features. Most are in such a state becuase nobody has suggested they upgrade. And, therefore they stay.
There are also some plugins that have not been updated and may use functions or replaced in later versions of PHP. I have come across this a few times. A plugin developer using a method that was popular 10 years ago, but not used now must be seen as ‘out of touch’ and encouraged to ‘update their skills’. Site owners should replace these plugins with more modern equivilents.
Here, tkaen from wikipedia, is a list of the versions, amd the dates that support for them stops. V5.5 is the oldest supported version today.
|Version||Date Relased||Support ends on|
|1.0||8 June 1995|
|2.0||1 November 1997|
|3.0||6 June 1998||20 October 2000|
|4.0||22 May 2000||23 June 2001|
|4.1||10 December 2001||12 March 2002|
|4.2||22 April 2002||6 September 2002|
|4.3||27 December 2002||31 March 2005|
|4.4||11 July 2005||7 August 2008|
|5.0||13 July 2004||5 September 2005|
|5.1||24 November 2005||24 August 2006|
|5.2||2 November 2006||6 January 2011|
|5.3||30 June 2009||14 August 2014|
|5.4||1 March 2012||3 September 2015|
|5.5||20 June 2013||21 July 2016|
|5.6||28 August 2014||31 December 2018|
|7.0||3 December 2015||3 December 2018|
|7.1||1 December 2016||1 December 2019|
So, why does it matter?
Why would you want your WordPress site to be using 10 year old code. You want the latest servers from your hosting provider, so they should be using the latest software for your also. it takes very little effort to update in most cases there will be an option box in your Cpanel settings. If you are unsure, ask your hosting provider, they shouold be happy to help.