Coders, web developers, and Android geeks love this sort of thing, but I'll imagine quite a few of you are asking yourself what these new delta updates mean for me, and do I need to do anything or worry about it? A delta update is a broad term that means only changes to a package will be downloaded and the changes will be merged into the existing files inside the package.In this case, the package is the apk file that's installed on your phone.
This suite contains 'debdelta-upgrade', that downloads deltas and use them to create all Debian packages needed for an 'apt-get upgrade'. The server generates deltas by looking at the current state of the archives and at the state before (precisely, up to 40snapshots before, ~10days) and it generates all deltas needed to upgrade.
It also (daily) deletes all deltas that would upgrade to a package version that is not present in the archive any more, and all deltas older than 50 days.
debdelta is an application suite designed to compute changes between Debian packages.
These changes (that we will call 'deltas') are similar to the output of the "diff" program in that they may be used to store and transmit only the changes between Debian packages. The source is made available using There is a server that generates deltas for upgrades of packages in the Debian repository archives.
In the initial implementation machines using image based updates won't be able to install extra packages from the archive as we're still discussing ways to support overlaying extra packages on top of the base system.
However image based systems will be able to opt-out of image updates and switch to apt-based updates thereby allowing installing extra packages.
You are effectively just noting what changed between two files (that's called delta encoding).
For example, if the app contains many resources, then those don't usually change for smaller updates, and only the executable code itself needs to be transferred.
If you pass rsync two local paths, it will default to using "--whole-file", and not delta-transfer. (otherweise a temporary copy is built up, and only then the old target file delete and the tempopary copy renamed.