Modders please remember to test your code in a Zen Cart 1.5.6 environment. Don't assume that just because you have fixed PHP7 warnings that your code will interoperate perfectly with Zen Cart 1.5.6 if it was written for an earlier version.

In advance of a release of the first patch to Zen Cart 1.5.6, please be sure to also check Github for bugfixes to core files you might be changing.