Q4 2026 Deadline Calendar: Google, Meta, Microsoft, Reddit

Six platform changes fall between October 1 and December 31, 2026 that marketing teams should plan around, and most of them hit the tools behind the ads rather than the ads themselves: API versions that expire, a bid setting that disappears and Reddit’s RSS feeds going dark on November 13. Six more are already dated for early 2027. Each date below comes from the platform’s own page.

The table lists each dated change, what it is and who needs to act. Most rows matter to whoever owns your reporting, feeds and integrations, so share it with them as well as the media team.

Reddit’s Help Center says it will stop supporting RSS feeds on November 13, 2026, and points moderators to a Discord or Slack alert app instead. For marketers, RSS is often the quiet plumbing behind subreddit monitoring, brand-mention alerts and social listening dashboards. Anything built that way stops updating on that date.

Earlier, on October 31, Reddit stops accepting new requests for public Data API access, per its September 30 developer announcement. Update, October 3, 2026: this date first ran as reported; we have since confirmed it in an Internet Archive copy of that post, captured the day it was published. Its later steps, removing access for unregistered apps from January 12, 2027 and ending the public API in March 2027, are covered in our breakdown of Reddit’s deadlines.

Ad platforms release new API versions on a schedule and switch off old ones. When a version expires, any dashboard, script, bid tool or feed connector still calling it stops working until it is upgraded. Two expire this quarter.

• Meta Marketing API v24.0, October 6. Meta’s versions page lists v25.0, released February 18, 2026, as the newest Marketing API version.
• Google Ads API v22, October 2026. Google’s sunset schedule marks the date as tentative. Version 25.2, released September 23, is the newest version already out.

Most teams do not call these APIs directly; their reporting and management tools do. A one-line question to each vendor (which API version are you on, and when do you upgrade) covers it.

From October 1, Microsoft Advertising no longer offers a maximum cost-per-click cap when you create a new campaign that uses Maximize Conversions with a target CPA, Maximize Conversion Value with a target ROAS, or Maximize Clicks, unless it uses a portfolio bid strategy. Microsoft’s August product update says existing campaigns that already use the cap keep it.

The practical effect: if your team relies on a bid cap to stop an automated strategy overspending on single clicks, new campaigns now need a portfolio bid strategy to keep that control. The same post covers Microsoft’s AI Max for Search, which we compared with Google’s version in our AI Max comparison.

Several bigger changes land just after the quarter ends. Planning for them belongs in Q4, because each needs work before the date.

Two of these moved. Google first planned to auto-upgrade Dynamic Search Ads to AI Max from September 2026, then pushed the DSA sunset to February 2027 after advertiser feedback; campaigns using automatically created assets and campaign-level broad match still began upgrading in September. The Merchant Center image rule is stated on Google’s image requirements page: products need images of at least 500 by 500 pixels from January 31, 2027. Our Q3 deadline calendar has the changes that came before this quarter.

None of these changes is large on its own; the risk is a report or alert that stops without anyone noticing during the busiest selling weeks of the year. Put each date in the shared calendar with an owner. For help auditing which tools and feeds depend on these platforms, our analytics and paid media teams can review your stack.

Most of the dates in the calendar land on tools the marketing team does not operate directly: a reporting dashboard, a bid-management platform, a feed connector, a listening vendor. The routing above says to ask each one a one-line question, and the question works only if it is specific. “Are you ready for the API changes?” gets a reassuring yes. “Which Meta Marketing API version do you call today, and on what date will you move off v24.0?” gets an answer that can be checked against Meta’s versions page.

Ask it in writing, once per vendor, with the dates from the table attached. For ad-platform tools the question is the API version and the upgrade date. For anything that reports on Reddit it is the data source after November 13 and after March 2027, as the callout in the Reddit section puts it. For bid tools on Microsoft Advertising it is whether new campaigns are created with a portfolio bid strategy where a cap is needed. Keep the replies with the calendar entry, so that when something stops later in the quarter the owner knows which vendor said what.

A vendor that cannot answer is itself a finding. It does not mean the tool will break; it means nobody on either side knows whether it will, and that is the state the calendar exists to remove before the busiest weeks of the year.

Expect the answers to arrive at different speeds. Some vendors publish the API versions they support, which answers the question without a ticket; others will need a written request and some time to reply. Send the questions now: the Meta date on October 6 is too close for a slow reply, so check that one against Meta’s versions page directly, and let the slower replies land before the Reddit dates of October 31 and November 13.

The illustrative cases below each involve a date from the table and a team that knew about it. They are the ways a known deadline still produces a surprise.

The quiet feed: a brand-mention alert built on a subreddit RSS feed stops on November 13, nobody notices because the alert tool simply shows no new items, and the gap is discovered in the January review. The mid-quarter dashboard: a reporting tool still on Meta Marketing API v24.0 breaks on October 6, in the second week of the quarter, and the first anyone hears of it is a blank chart in a Monday report. The assumed cap: a team creates new Microsoft Advertising campaigns in October expecting to set a Max CPC as before, finds the option gone on those automated strategies unless they use a portfolio bid strategy, and launches without the control rather than rebuilding on a portfolio strategy. The January images: Merchant Center products with images under 500 by 500 pixels are left for the new year, and the January 31 deadline arrives during the post-holiday reporting crunch with hundreds of warnings to clear.

The first two are caught by the vendor question, asked in October. The third is avoided by reading the Microsoft section before the next campaign build. The fourth is the reason the early-2027 rows are in a Q4 calendar at all.

What the four have in common is that the date was already on a platform page before it arrived; the surprise in each case comes from a team that had the date and not an owner for it, which is the omission the calendar entry format in the callout below is designed to remove.