PHP 7 upgrade, impact on Contao?

My ISP has informed me that they are upgrading PHP from 5.6 to 7 next week. I'm babysteps so have no idea what impact, if any, it will have on my Contao website. We're (I'm afraid) still on 2.11.

Any insights?

ps. There is a downgrade option that can be set in the .htaccess file but it is only a temporary reprieve as that will go away in 2017.

I would not expect that Contao 2.x will be able to run under PHP 7. IMHO, the first version being able to do so is 3.5.2.

Even if, I would expect any of the old extensions to crash - so, your option should be to pay for the downgrade option and upgrade to Contao 3.5 LTS as soon as possible. Sorry to say that.