ExpressionEngine v2 was retired October 13, 2016. After this date, the system is no longer receiving updates. ExpressionEngine v3 has now entered End of Life (EoL) phase and will be retired December 14, 2018. With the launch of ExpressionEngine v5, v4 is now End of Life and due to be retired on November 16, 2019.
If you're not sure of the consequences of doing that upgrade, we can perform a full site audit and advise you on the best way to perform the update, what add-on incompatibilities there might be and give you an upgrade path to the latest and greatest version.
There is no magic bullet when it comes to upgrades. Not all v2 add-ons have been upgraded to v3 or v4 and there is no magic bullet to achieve this. However, with a combination of custom development and reworking of existing functionality, we're confident that all sites can be efficiently upgraded.
The best thing of all is that once we've supplied the assessment, if you then decide to work with us to action your upgrade path, we'll refund 100% of the Assessment fee!