If you want to see a big, comprehensive overview of all the visual tweaks Google has made in Android M so far, we’ve got your hookup here. But for the vast majority of phones that don’t use Google’s UI, what else does M bring to the table?

Google has already covered a few of them, including the new permissions system, the fingerprint scanner API, and improved idle battery life. We’ve covered a couple more in some detail, including the new backup system for app settings and data and the support for USB Type-C and MIDI devices. Today we’ll highlight a few more—these changes won’t all be universal, but chances are there’s an under-the-hood improvement or two in Android M that will change how you use the platform.

Bluetooth stylus support

Good news for you stylus people: Android M now natively supports Bluetooth styluses. According to Google’s developer documentation, “position information from the touch screen is fused with pressure and button information from the stylus to provide a greater range of expression than with the touch screen alone.”

This should be handy for note taking and drawing on Android tablets. Samsung’s Galaxy Note series has been fairly successful, so the demand for good stylus support is certainly there.

Bluetooth 4.2

Like Bluetooth 4.1, version 4.2 is another relatively minor addition to the spec that focuses on adding just a couple of small features. Support for Bluetooth Smart data packets can increase transfer speeds by “up to 2.5 times,” though existing Bluetooth 4.x hardware may not support it. Bluetooth 4.2 also adds support for IPv6 and 6LoWPAN, and Bluetooth 4.2 devices can communicate directly with one another without the need for any kind of intermediary phone or computer.

That last bit will be important if Google’s new Brillo OS for smart devices runs a cut-down version of Android M. The last couple of Bluetooth releases have been focused on better support for the “Internet of Things,” so it would make sense for Brillo to take advantage of them.

4K Display Mode

Apps in Android M can now request 4K resolutions on compatible hardware—for now, that means a top-end mobile SoC like Qualcomm’s Snapdragon 810 or Nvidia’s Tegra X1. This feature should prove particularly useful for Android TV boxes as 4K content and TVs slowly become more mainstream. The X1 is already shipping as a part of Nvidia’s Shield set-top box.

5GHz portable Wi-Fi hotspot

This is one of the features buried in the big "M" shown at the top of this article, and it’s pretty self-explanatory. Mainstream smartphones have included dual-band 802.11n or 802.11ac Wi-Fi for some time, but the Wi-Fi hotspot feature still uses the more widely compatible but more-congested 2.4GHz band.

When you configure your Wi-Fi hotspot in Android M, the system will now ask you to specify whether you want to use the 2.4GHz or 5GHz band in addition to the name, type of encryption, and passkey you want to use. Our Nexus 5 only appears to offer the 2.4GHz band, though, so it’s possible that this won’t be supported on all hardware (or that it’s just not quite ready in this preview build).

The way SD card support should be

Android has generally been hostile-to-indifferent about external storage devices for the last few years. Almost all Nexus devices have steered clear of SD cards entirely, and the OEM phones that include slots have to contend with clunky, manual file management and apps that can’t always use the SD card as a storage target (either for the app itself or its data or both).

Enter something called “Adoptable Storage Devices.” If your devices use what Google software engineer Jeff Sharkey calls “storage devices in long-term stable locations” like internal SD cards, Android M can “adopt” that storage device, encrypt it, and then use it in exactly the same way that Android treats internal storage currently. This means you can move any installed app and its data out to the SD card, and Sharkey’s post indicates that the entire /sdcard directory can be migrated to external storage if you want.

We’re sure this will make users of high-end flagships with SD card slots happy, but the primary beneficiaries aren’t going to be the people who want to turn their 32GB Android phones into 288GB Android phones. Rather, it seems aimed specifically at the “next billion” smartphone buyers Google goes on about.

Consider how irritating it is to manage storage on the original Moto E, which included about 2GB of usable internal storage. SD cards can be added, but data needs to be transferred there mostly manually. The same phone with Android M could pick up another 16GB or 32GB of inexpensive external storage and treat it just like internal storage, making the user experience better without adding to the base price of the phone.

The primary downside of this feature is that SD cards are typically slower than internal storage; encrypting that storage will slow it down further. Whether that slowdown will be visible to the user depends on a long list of variables, including the speed of the SD card, the speed of the interface, and whether the SoC supports hardware encryption and decryption acceleration.

If you're testing on a Nexus device, there’s an ADB shell command you can run to make a removable USB drive “adoptable” so you can test the feature without an SD card slot. It’s available in Google’s documentation.