This blog is the latest in a recurring series that provides details about recent Store trends across categories, markets, and more. Understanding these trends can help you determine what types of apps to build or where to focus your development efforts. Data from the Windows Store is presented alongside the Windows Phone Store, allowing you to make better decisions for all the apps you publish regardless of the device(s) you target.

This December update includes several new analyses: downloads by phone memory size, downloads by phone model, benefits of carrier billing, and analysis of the best revenue-generating prices used for in-app purchase items.

Windows and Windows Phone 8.1 Adoption Trends
Windows: Windows 8.1 is now the primary operating system for Windows Store. In November the vast majority of downloads (approx. 92%) of Windows Store apps were from customers running Windows 8.1.

Windows Phone: Windows Phone 8.1 now represents 65% of Windows Phone downloads while downloads from Windows Phone devices running 7.x account for less than 5%.

Windows and Windows Phone 8.1 provide the benefit of increased functionality for customers, and universal Windows apps for developers. Writing your app for 8.1 on any device allows you to easily convert to a universal project and manage one set of source code to target both Windows and Windows Phone.

Targeting Windows and Windows Phone 8.1 also offers enhancements to make development easier, such as using XAML and WinJS. With 8.1 now the primary OS version for both platforms, it is a great time to upgrade your 7.x and 8.0 apps.

The two graphs below show the download source for both Windows and Windows Phone apps and games, and the increasing adoption of Windows and Windows Phone 8.1.

Windows and Windows Phone app download source – Worldwide, Nov. 2014

Windows Phone Device Breakdown
Another increasingly important element to think about is the variety of Windows Phone devices available and their capabilities. The most common Windows Phone device today is the Lumia 520, representing more than a quarter of all app downloads.

This chart shows the percentage of downloads by device memory. It’s important to note that for Windows Phone 7.x devices a low-memory device is defined as 256MB or less of RAM, but on 8.x devices low-memory is 512MB or less of RAM, and the chart accounts for this distinction. With 71% of downloads now coming from low-memory devices, you can more than double your potential market by optimizing your app to run on low memory devices. If that’s not possible, consider creating a version with lower memory requirements to offer alongside your primary apps.

App downloads per phone memory – Worldwide, Nov. 2014

Low-memory devices account for the top five devices based on total downloads, and seven of the top ten. The chart below shows the top phone models by memory type, and the percentage of downloads from each.

Downloads by phone model and memory – Worldwide, Nov. 2014

Downloads Per Category
In November, Games was the most popular category for all devices, followed by Tools & Productivity, Music & Videos, and Social. Since we’ve begun posting these trend updates, we’ve seen categories and rankings become fairly stable. The main exception has been the Game category for Windows, which continues to grow and now accounts for 42% of all downloads on Windows.

Downloads per category – Worldwide, Nov. 2014

Categories with Highest Incremental Download Opportunity
It’s also helpful to understand which categories have the highest ratio of downloads per app. This is a function of total downloads versus total available apps in that category. For example, while Games is the most-downloaded category, Social has more downloads per available app.

Index of average number of downloads per app, in each category – Worldwide, Nov. 2014

Social is currently the #1 category in both Stores, with Photos, Games and Tools & Productivity in the top five for both Stores, a trend that has been steady for the past 6 months. If your goal is to reach the maximum number of downloads possible, analyze these categories to understand which present the highest potential for your apps.

Downloads by Market
Windows Store is available in 242 markets, and Windows Phone Store in 191 markets. As you localize your apps for consumers outside your home market, consider which other markets are generating the largest number of downloads and if they might be relevant to your apps.

Index of average number of downloads per app, in each category – Worldwide, Nov. 2014

The market with most downloads is United States, though the distribution of downloads shows there are many markets generating a significant number of downloads, such as China, India, France, United Kingdom, Brazil, Mexico and Russia. That doesn’t mean, however, that you shouldn’t consider other markets as well. Your apps may have specific characteristics more suitable to these markets.

Expansion of Carrier Billing: first in China, India and Brazil
Many of the markets with high number of app downloads have low credit card penetration, making it difficult for these customers to purchase apps from most global app stores. The Windows and Windows Phone Store supports several alternate payment options including: Alipay, PayPal, and carrier billing (Windows Phone only) with 81 partners in 46 markets. Additions this December include Verizon Wireless in the U.S., as well as mobile carriers in new markets such as India, Vietnam, Brazil, and China, all of which are in the top Windows Phone markets. With these additions, the Store now has established connections with 46% of all subscribers worldwide, more than any other major smartphone platform supports today (Source: Ovum World Cellular Information Service). For more information about recent carrier billing announcements and the customer reach potential, please refer to this blog post: Windows Store is first to bring carrier billing to China, India and Brazil.

Languages of Windows Store Customers
Language is a key driver of downloads and adoption. You can extend the reach of your apps by supporting additional languages.

Primary language of Windows Store customers – Worldwide, Nov. 2014

Offering your apps in English only will reach roughly 25% of Windows Phone customers, and a larger percentage of tablet and PCs users (add %here). Adding Spanish, Mandarin, Brazilian Portuguese, and Russian increases coverage to more than 50% of Store customers.

Don’t know where to start? Learn how to localize your Windows and Windows Phone apps.

Monetization Options
Another important decision is which monetization model or models to adopt: paid apps, in-app purchase, or in-app advertising (showing ads in the app). Revenue analysis from November 2014 shows that all three models are generating significant revenue, though in-app purchase and advertising generated the most revenue.

For both Windows and Windows Phone Stores, advertising is a growing source of revenue, and in November it rose to 53% of total revenue. It’s important to note that November and December are the months where advertisers tend to increase their spending, which can account for part of the growth.

In-app purchase of durable and consumable digital products is also an increasing source of revenue, and generates significantly more revenue than paid apps. Currently, all the top 20 apps and 88% of the top 50 apps use in-app purchasing.

Paid apps continue to decline as a percentage of overall revenue as well as in absolute revenue. In August 2014, paid apps generated roughly 20% of developer revenue, dropping to 11% as of November 2014.

Developer payout by source – Worldwide, Nov 2014

If your Windows Phone apps generate revenue from ads, we encourage you to implement Windows ad mediation, a simple solution designed to help you manage multiple in-app advertising SDKs while increasing ad fill rate and revenue. In our testing, ad mediation delivered a fill rate of over 95% as well as a revenue increase of up to 200%. Of course, results vary by market and app.

The April 2014 //build presentation, ‘Maximizing Revenue for Phone, Tablet and PC Apps in the Windows Store’ has more detail about the different revenue models, and shares best practices for choosing a model and then optimizing for maximum revenue.

In-App Purchase
In-app purchase is becoming a staple in both Windows and Windows Phone apps, across a wide range of options and price points. Today, in-app purchases account for 35% of developer revenue.

In the Windows and Windows Phone Store Trends – September 2014 blog we shared that all of the top 20 highest grossing apps were using in-app purchase, along with 44 of the top 50 highest grossing apps. And, the revenue generated from in-app purchase continues to increase month over month.

This month we investigated the in-app purchase price points that generate the most revenue. We found that lower price points do not necessarily lead to higher revenue. While the majority of in-app purchases in the Windows Phone Store are at price points below $2.00, the top 3 highest grossing price points, ordered by total revenue, are $9.99, $4.99, and $19.99. In short, in-app pricing does not have to be low to be profitable.

Source: Top in-app price points, Microsoft, Worldwide, Nov 2014*

*Top 10 highest revenue price points in Windows Phone apps and games, in order of total revenue: $9.99, $4.99, $19.99, $1.99, $0.99 $49.99, $79.99. $99.99, $2.99, $3.99. Revenue is a result of number of apps using the price point, the number of times the in-app item is purchased, and the price of the item.

For Further Analysis
We recommend you take some time to browse through the app catalog in the categories you want to develop for, analyzing the top apps in each category to see what makes these apps successful based on the trends data provided.

We also suggest you begin developing for Windows 8.1 and Windows Phone 8.1 as it is quickly becoming the primary operating system for customers. The best way to do this is to create universal Windows apps, which allow you to develop and edit with one source code for both platforms. For your Windows Phone apps, we also strongly urge you to consider using Windows ad mediation or the in-app purchase model to increase your app revenue.

We hope this data can help inform your decisions on investment areas for new apps and app updates. Please share your ideas on additional data that would help you keep building better Windows apps. We expect to add more analyses in the future, so your ideas will help us plan our upcoming quarterly updates.