The phrase "adding improvements" is correct and usable in written English.
You can use it when discussing the process of making enhancements or upgrades to something, such as a project, product, or system.
Example: "The team is focused on adding improvements to the software to enhance user experience."
Alternatives: "implementing enhancements" or "making upgrades".
Nissan is adding "improvements for range management," without actually providing a bigger battery in the Leaf.
But Mr. Golvin said that Apple was adding improvements to battery life and other enhancements to software that people would actually find useful.
Shoe manufacturers keep adding improvements to shoes in the form of cushioning gel pods, microprocessors and so-called thrust enhancers, but these upgrades don't seem to make runners safer.
He also said it's been adding improvements like next-day delivery, recipe content and a new iOS app.
Glu acquired PlayFirst for $12 million in stock this last spring and the new game owners quickly started adding improvements and new characters to the popular time-sensitive game series.
FriendFeed sparked the whole lifestreaming movement this year, and kept adding improvements that makes it easier to filter the Web through the actions of everyone in your various social networks.
Instagram have also added improvements to its editing tools.
The Obama administration added improvements, including lofty promises to restore spawning streams and estuaries.
Contractors estimated that it would take $1 million to make basic repairs and about double that amount to add improvements, like an elevator and new bathrooms.
In my line of work (landscape architecture) I have helped defend clients hoping to add improvements and I have also aided people resisting new projects.
The Pocket PC Phone version builds in the GPRS phone and adds improvements Microsoft designed for its smartphone, which stops you losing the data connection when the phone goes to sleep.
