Just in time for the holidays and facing heavy competition from Barnes & Noble’s upcoming Nook e-book reader, Amazon has announced that it has improved the Kindle’s battery life when the wireless connection is turned on and will now be offering native PDF support for its e-book reader. Both the battery-life boost and native PDF support will be available to owners of new Kindles and some older models via a firmware upgrade. In a press release, Amazon says the Kindle now has battery life of up to seven days with wireless turned on compared with four days previously. However, battery life with wireless turned off remains the same (around two weeks).

“Battery power management for portable wireless devices is a complex technical area, and the battery life improvement announced today is the result of a six-month firmware improvement and testing program,” the release notes. As for the native PDF support, Amazon says you can now “read professional and personal documents in their original PDF format without conversion.” To read PDF files, you either e-mail them to your Kindle e-mail address or move them over using a USB connection. If you prefer to have your PDF documents converted to the Kindle format, you type “Convert” in the subject of the e-mail. All new Kindles will ship with the battery-life improvements and native PDF support in place, but if you bought an earlier Kindle you may be eligible for both enhancements via a firmware upgrade that will automatically download to your Kindle when you turn its wireless connection on.