Where will changes and fixes to guides and manuals for 5e be found? I'm interested in a grappler build, among others, and don't know where to look to see if the last bullet for the grappler feat has been changed. The grappler example aside, it should be useful to know for future fixes.
[RPG] errata posted/published
dnd-5eerratawizards-of-the-coast
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Look closely at the errata, though, because it's not all created equal. I think there's several types of errata.
For example, some errata is on the order of "replace the sentence about "At Will Power" to say "At Will Attack power". Wizards of the Coast makes Magic The Gathering, and because of the way that game is played, exact wordings are important, so this is something they do. Rewordings and clarifications make the game clearer and get the intent across better.
The second type of errata is "whoops, that's a typo". For example, when the View Object ritual was printed it said "1000 gp" for the component cost, and then in the listing it said "5000 gp". It turns out 5000 gp was what was meant. This is very important errata, because it could throw numerical and systematic values off.
Another type of errata is "we changed our mind"- the tiefling racial ability Infernal Wrath went from being some bonus damage to an immediate reaction encounter power. That's a big change- that's the kind of thing that changes how the game works. The motivation for this type of change is that "here's something we didn't think about enough originally- this way will be a bit better than the way we originally planned it". Would the original version of Infernal Wrath wreck your game? I tend to think it wouldn't.
Then there's the last type of errata- which is related to the previous type but it says "we designed this wrong. We'll have to fix it because it could cause a major problem if abused". This is where powers like Blade Cascade got tightened up. I think this is important as well.
In the case of the 4e Errata, most of the errata contains a sentence or two to clarify the thinking behind it. (For example check out why Careful Strike gets a damage bonus.. they explain that it makes it a viable choice compared to twin strike). This is good commentary,. you might agree or disagree, but it's usually interesting to hear why they changed things.
Somewhat oddly, your question is answered by the Sage Advice Compendium document which was first released as part of a Sage Advice article by Jeremy Crawford on the official D&D website entitled Rules Roundup.
This document says the following on the first page, under the "Errata" heading:
A corrected version of the book includes the following text toward the bottom of its credits page:
This printing includes corrections to the first printing.
At the time of writing this answer, there have only been two printings of the Player's Handbook: the original, and the latest which incorporates the errata updates. Any rules clarifications which are not considered errata are going to continue to be found in the updated versions of the Sage Advice Compendium document. The latest version is always accessible from the official D&D website, and includes a version number both in the file name and in the footer of the document. The latest version always takes precedence over previous versions. Note that the errata document can also be distinguished from later updates by its version number, which is also contained in the file name as well as the footer of the document.
Best Answer
The most recent version of the Sage Advice Compendium will contain a list of links to errata for individual books
Wizards do not maintain a single up-to-date reference page which lists all the current errata or how to find it. However, their Sage Advice Compendium PDFs contain a list of links to the most recent (as of publishing) errata documents for all official 5e products; the best way to find errata is to check the most recent version of the SAC, revisions of which should be published in articles in the "Sage Advice" section of the WotC website.
As a general rule, most errata documents are announced/published in Sage Advice articles before being referenced in updates to Sage Advice Compendium, and those articles are not obviously updated when later errata affecting the same resources is published (though the files they link to may change to newer versions without notice). In some cases Wizards have announced new errata solely by announcing a new SAC version with the new links, as in the November 2020 update. The December 2021 update announced new errata while simultaneously linking to a new version of the SAC (and, despite calling it a Sage Advice article, didn't actually put it in the Sage Advice section of their site).
This all makes trying to search the internet for relevant errata quite annoying, especially as the order in which the articles are indexed by search engines does not necessarily put the most recent version at the top of the list.
(It must also be noted, as per Akixkisu's answer, that the official errata documents do not actually document all of the changes in text that have been introduced in newer printings of some 5e books, including changes that some consider significant.)
As of this edit, the most recent version of the Sage Advice Compendium is v2.7 (~December 2021), but this will undoubtedly be superseded in the future. The list of errata links from this version is reproduced below.
For those interested in reviewing the history of the SAC, the answers to this question include a list of links to archived versions of the SAC and some examination of the changes between them.