ES changes in 3.0 --> affecting current gear?

Sometimes changes to item statistics affect currently existing items retroactively and sometimes they do not (creating "legacy items", e.g. Kaom's Heart with +1000 life). I am not sure when which version applies.
In the upcoming changes to 3.0, can we expect currently existing Energy Shield-based items to be changed so that their inherent boni to ES get reduced, or will these continue to exist unchanged as "legacy variants"?

thank you

It has to do with how item data is stored on the servers. Basically, changes to the value of mods, or additions or removals of mods, usually cannot be retroactive (although GGG have been able to get around this in some cases for reasons I won't go into unless you're particularly interested). Mechanical changes to mods, or changes to the stats of the base item, are necessarily retroactive.

The changes to ES mods won't apply to existing items. However, the base ES of some items has also been reduced, and that will apply to all existing items.