I am upgrading from PHP 5.x to 7.0.27
and Zen Cart 1.5.4 to 1.5.5f (attempting to follow the official upgrade procedure since I have several add-ons)

I've used this shipping rate zonetable add-on successfully since about 2010(yeah!) for two simple price zones USA-Mainland and AK-HI-Canada.

In the process of testing the upgrade caught this debug error:
Code:
Uncaught Error: Call to undefined function split()...in ..../includes/modules/shipping/zonetable.php:124
As best as I can tell, this add-on hasn't been modified since 2007, but has definitely worked with my previous version of PHP. I looked thru previous postings and did not see this specific error mentioned.
If other relatively non-techie users have the same issue, this is what worked for me to fix it. (nope, I don't really understand what I'm doing, I just looked at post #304 above for code differences around (my) line 124.

around line 124 of /includes/modules/shipping/zonetable.php
Code:
$table_cost = split("[:,]" , constant('MODULE_SHIPPING_ZONETABLE_COST_' . $this->dest_zone));
	to
	$table_cost = preg_split("/[:,]/" , constant('MODULE_SHIPPING_ZONETABLE_COST_' . $this->dest_zone));
As an aside - it appears that there hasn't been activity on this add-on for a couple years. Are users preferring a different solution now? Perhaps the "Table Rate Clone"?