Automatic Online Upgrade

I installed Acrobat Reader 9.0 last month,

Each time I open a pdf document, I get small icon which says some updates are available,

If I say, it goes ahead and install the updates.

Anyone know what is the technology behind this , any paper开发者_Python百科, details.

Nothing fancy, when you launch the program it "phones home" to Adobe and checks its current version against the latest one available. Typically it's a simple HTTP exchange, although some products may use something besides HTTP/HTTPS.