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Email Client Market Share in October 2021: Updates and More


Welcome back! It’s time for us to recap the previous month and see what shifts happened with email client market share.

This time, we’ve got an exciting update to share: We recently launched our new and improved email client market share site to include Apple’s Mail Privacy Protection (MPP) data, pre- and post-MPP launch.

Read on to learn about the updates, how you can use email client market share, and what shifts we saw in October 2021.

What changed with Litmus’ email client market share site?

Over the years, Litmus has reported on email client market share to help marketers make better decisions when it comes to strategy and prioritization for design, coding, and overall email program focus—both on our email client market share site and this blog series, which looks at the data on a month-to-month basis.

On September 20, 2021, Apple’s Mail Privacy Protection (MPP) went into effect, impacting Apple Mail users on iOS 15, iPadOS 15, and macOS Monterey devices, regardless of email services. This meant marketers would no longer be able to see reliable open rates, open times, geolocation, or device usage for users who opt into MPP—impacting the way Apple market share is analyzed.

As a result, we’ve updated our email client market share site to include post-MPP data as well as historic, pre-MPP data (you can check it out here).

Is email client market share still useful?

You might be thinking: Is email client market share useful, if a significant portion is impacted by MPP?

The answer: Yes! Although MPP is impacting (and will continue to impact) the way Apple market share is analyzed, we’re still able to glean valuable insights with the data we pull from Litmus Email Analytics.

And, although these are powerful insights on the industry as a whole, the real power lies within your analytics—that is, your audience. Use email client market share as a macro-level resource but also a tool to you help you better understand your subscribers’ behaviors.

Top email clients

With the introduction of MPP, we’re now grouping Apple iPhone (iOS Mail), Apple Mail (macOS Mail), Apple iPad (iPadOS Mail), and Apple Mail Privacy Protection (MPP-impacted opens) under “Apple.” Why?

These three Apple email clients—iOS, iPadOS, and macOS—are historically in the top 10 email clients. Now with Apple Mail Privacy Protection (MPP-impacted opens) in the mix, it will eventually show a significant increase in its market share as adoption increases, which is not necessarily an accurate reflection as those opens are inflated due to MPP.

So, to help with consistency moving forward, we’re grouping all Apple email clients together, including Apple Mail Privacy Protection (MPP-impacted opens) since we know that overall, Apple remains to possess the greatest market share.

As we shared last month in our September 2021 email client market share blog, there two key things to note: 1) MPP hides device data so we can’t differentiate between iOS, iPadOS, or macOS, and 2) the new OSes also don’t differentiate between MPP and non-MPP in the user agent data it passes.

Top 10 Email Clients in October 2021

Now that we’re grouping Apple email clients into one category, the top 3 email clients look a bit different. Previously in fourth place was Outlook, which has been the case from the first quarter of 2021, but it now joins the rank as one of the top 3 email clients.

  1. Apple: 51.4%
  2. Gmail: 33.7%
  3. Outlook: 5.3%
  4. Yahoo Mail: 2.8%
  5. Google Android: 2.3%
  6. 1.2%
  7. Samsung Mail: 0.6%
  8. Windows Live Mail: 0.1%
  9. 0.05%
  10. GMX: 0.04%

Here’s a breakdown of Apple email clients:

  1. Apple iPhone (iOS Mail): 27.36%
  2. Apple Mail Privacy Protection: 14.35%
  3. Apple Mail (macOS Mail): 8.78%
  4. Apple iPad (iPadOS Mail): 0.91%

Opens by environment

As we’ve mentioned, MPP prevents marketers from seeing device usage (aka, where opens are coming from), so we aren’t able to differentiate between reading environments. That’s why we’ve created a separate category for Apple Mail Privacy Protection.

Opens by environment

Since its launch in September, MPP adoption has increased as people upgraded their Apple OS. Compared to September, Apple Mail Privacy Protection’s share jumped from 6.6% to 14.2% in October.

As a result, market share across all other reading environments have decreased. Webmail saw a slight drop from 40% to 39.8%, while mobile fell from 36.6% to 30.7%. Desktop decreased from 15.8% to 14.0%.

  1. Webmail: 39.8%
  2. Mobile: 30.7%
  3. Apple Mail Privacy Protection: 14.2%
  4. Desktop: 14.0%
  5. Other: 1.3%

Most popular mobile opens

When looking at mobile, the top 3 most popular clients are Apple iPhone (iOS Mail), Google Android, Apple iPad (iPadOS Mail), as expected.

Apple iPhone (iOS Mail) still holds a majority of the market share, though it did see a decline from 89.9% to 87.9%. Google Android increased from 5.6% to 7.3%, while Apple iPad (iPadOS Mail) stayed the same at 2.9%.

Most popular mobile opens

  1. Apple iPhone (iOS Mail): 87.9%
  2. Google Android: 7.3%
  3. Apple iPad (iPadOS Mail): 2.9%

Most popular webmail opens

Over in webmail, the three most popular webmail clients are Gmail, Yahoo Mail, and Outlook—similar to previous months.

Most popular webmail opens

Although Gmail holds steady in the #1 spot, it did see a decrease, dropping from 89.6% in September to 89.1% in October. Yahoo Mail increased its share slightly from 7.2% to 7.5% as did, from 3% to 3.2%.

  1. Gmail: 89.1%
  2. Yahoo Mail: 7.5%
  3. 3.2%

Wondering why we categorize Gmail as webmail? Learn how Gmail opens are reported in Email Analytics.

Most popular desktop opens

The top 3 most popular desktop opens remain the same: Apple Mail (macOS Mail) in first with a majority of the share, Outlook in second, and Windows Live Mail in third.

Most popular desktop opens

Apple Mail (macOS Mail) went down a few percentage points, from 64.5% to 61.8%. In contrast, Outlook’s market share increased from 34.6% to 37.2%, as did Windows Live Mail, growing slightly from 0.7% to 0.8%.

  1. Apple Mail (macOS Mail): 61.8%
  2. Outlook: 37.2%
  3. Windows Live Mail: 0.8%

Light Mode vs. Dark Mode opens

As of September 2021, we were able to start tracking Dark Mode usage on a more regular basis.

Light Mode vs. Dark Mode

Light mode is the most popular setting, which was the case last month too, but with minor shifts: Light mode usage increased slightly, from 73.7% to 74.4%, and in turn Dark Mode decreased from 26.3% to 25.6%.

  1. Light Mode: 74.4%
  2. Dark Mode: 25.6%

As a reminder: Our Dark Mode data is based only on the Apple Mail app for iOS 13, macOS 13, iOS 14, macOS 14, iPadOS 14, iOS 15, iPadOS 15, and Apple Mail privacy-impacted devices.

Now look at your audience

Though email client market share provides powerful insights on the industry as a whole, the real value lies within, with your audience. The key is getting to know your subscribers—and one of the tools to help you do that is email client market share.

Small shifts over time can lead to big changes. Stay tuned next month as we share our findings and continue to track the impact of MPP.

Where did we get all this data? Our email client market share stats are pulled from over a billion email opens, anonymously collected and aggregated with Litmus Email Analytics from October 1-31, 2021. It highlights global trends across all industries and verticals. Some email clients may be over- or under-represented, particularly with mobile and webmail. This is due to image blocking or image caching, most notably with Gmail. Still curious? Learn how we get this data.

Get insights into your audience—with Litmus Email Analytics

Get visibility into your audience—Apple Mail and otherwise—so you can see how much your program is being impacted by MPP, adapt for the future, and continue to create more effective campaigns, faster.