We want to let you know about some upcoming changes to OneDrive. On August 10, 2016, the amount of storage that comes with OneDrive will change from 15 GB to 5 GB. We are also discontinuing the 15 GB camera roll bonus. You can learn more at our FAQ.
There is no action you need to take, because your OneDrive account is currently below the new storage limits. Even though you aren’t currently affected, we want to keep you updated on all important changes to OneDrive. If you’d like to check your account, you can visit the Storage page.
We realize these are big changes to a service you rely on. We want to apologize for any inconvenience they may cause you. We made a difficult decision, but it’s one that will let us sustainably operate OneDrive into the future.
source: Microsoft OneDrive Team