History of CR 614.17a
Every distinct wording since 2010, newest first.
May 3, 2019 · War of the Spark
“Can’t” effects must exist before the appropriate event occurs—they can’t “go back in time” and change something that’s already happened.
January 25, 2019 · Ravnica Allegiance
"Can't" effects must exist before the appropriate event occurs-they can't "go back in time" and change something that's already happened.
September 29, 2017 · Ixalan
“Can’t” effects must exist before the appropriate event occurs—they can’t “go back in time” and change something that’s already happened.
February 1, 2010 · Worldwake
rule 614.17a not present in this release