There is a big chance that we will never see D7 running on PHP7 because D7 is "abandoned". Just take a look at this issue. Basically no one cares about D7 anymore because all the small sites have fled to Wordpress and the big ones cannot keep on working with the shortcomings of D7 - so they are focusing only on D8.
There is a big chance that we will never see D7 running on PHP7 because D7 is "abandoned". Just take a look at this issue. Basically no one cares about D7 anymore because all the small sites have fled to Wordpress and the big ones cannot keep on working with the shortcomings of D7 - so they are focusing only on D8.