Seamless updates, a new Android N feature that Google revealed during its I/O conference this week, won’t be available on existing Nexus smartphones. The feature requires a dedicated storage partition, and existing devices simply don’t have one.

Borrowed from Chrome OS, seamless updates prepares the latest version of Android in the background as soon as it becomes available, then installs it when your Nexus restarts. You don’t have to download or update manually; Android N just takes care of it.

But to make this possible, the feature relies on a second storage partition where it can prepare your update without affecting the primary partition you’re using, according to Android Police — and existing Nexus smartphones don’t ship with one.

Now, it’s not impossible to add a second partition. You’ve probably partitioned storage drives yourself at some point in the past. However, adding one to a Nexus phone would require a lot of effort, and the average user may not feel comfortable carrying out the process.

There are also risks involved that Google will want to avoid. The last thing it wants is a whole bunch of angry Nexus users who have bricked their phones by trying to repartition them. For the same reasons, it’s unlikely the feature will come to existing third-party devices, either.

So, seamless updates will be reserved exclusively for new smartphones and tablets, which will ship with that second partition as standard. There may be unofficial methods of bringing it to existing devices later, but it doesn’t sound like Google will be offering one.