Trading Card Games are inherently complex game systems, due to the constant creation of new game pieces creating an exponential growth in the number of card interactions while simultaneously pushing the boundaries of the game rules.
Things will happen from time to time that warrant an update to a cards wording in order for it to function as intended. These factors could be the evolution of game or format rules, an oversight from our rules team, changes to templating best practice, or simply a mistake being made.
When a card's effect is updated, it is considered to have received an errata. The only reason we will errata a card is to insure the card functions in line with the intention of its design.
If a card has received an errata, all versions of that card should be played as though they have the errata'd card text.
Errata Bulletins only include cards that have received functional errata (errata that changes how the card works), and cards that have received significant changes to their templating and/or syntax, as to clarify that the changes are in fact non-functional. Errata bulletins do not include cards with minor text updates.