Updating to php7.1

@bashy hope you don't mind me tagging you in this as I saw you comment on the below related thread.

https://github.com/dompdf/dompdf/issues/1272

I am setting up a live server on digital ocean with Forge for my new app and have installed php7.1

Though after running some tests I realised that there was an incompatibility between my domppdf version and php7.1

domppdf is a dependency being pulled in by L.2 version of Laravel Cashier. I tried running 'compser update' but didn't see any update come through related to cashier or domppdf so then tried 'composer require dompdf/dompdf' and got the following response:

Using version ^0.8.0 for dompdf/dompdf
./composer.json has been updated
Loading composer repositories with package information
Updating dependencies (including require-dev)
Your requirements could not be resolved to an installable set of packages.

  Problem 1
    - laravel/cashier v6.0.18 requires dompdf/dompdf ^0.6.1 -> satisfiable by dompdf/dompdf[v0.6.1, v0.6.2] but these conflict with your requirements or minimum-stability
    - laravel/cashier v6.0.18 requires dompdf/dompdf ^0.6.1 -> satisfiable by dompdf/dompdf[v0.6.1, v0.6.2] but these conflict with your requirements or minimum-stability
    - laravel/cashier v6.0.18 requires dompdf/dompdf ^0.6.1 -> satisfiable by dompdf/dompdf[v0.6.1, v0.6.2] but these conflict with your requirements or minimum-stability
    - Installation request for laravel/cashier == 6.0.18.0 -> satisfiable by laravel/cashier[v6.0.18].


Installation failed, reverting ./composer.json to its original content.

Sorry for noob question but in this situation what is the best thing to do? I'm not ready to update L5.2 / cashier yet so is the only option to use php7 instead until I'm ready to update?

Thanks

Ralph