Fortigate, VPN, Chrome and Logjam

Hi

I have a Fortigate 3240C v5.2.3,build670 which I have set-up an SSL VPN (vpn.activatelearning.ac.uk) which works fine in IE. However after the latest Google Chrome update Chrome refuse to connect with the error message about a weak DH issue. If I check the site with https://weakdh.org I get a warning about a weak DH group.  I have seen the article http://www.fortiguard.com/advisory/2015-05-20-logjam-attack about Logjam.  I also note that the documentation for setting up the VPN does not list Chrome as one of the supported browsers.

My question is a lot of academic staff use Chrome as the default browser and using it they can no longer connect to the VPN.  Do you know if Fortinet are going to release a update or is there a fix already?

I checked the Fortinet site and it is patched ok and works fine with Chrome.

Thanks for any help

PS Yes I know they can use IE, but that then opens the question, is IE now less secure than Chrome....