I develop a themes app , and publish to my cydia source,
Any user download and install ,cydia will prompted to update (the version in the server is the same as the version user installed) ,can any one tell me why?

content of "control" file in my deb
========================================

Package: com.iThemeSky.iThemeSky
Version: 1.0
Name: iThemeSky
Essential: no
Icon: http://update.ithemesky.com/deb/icon@2x.png
Installed-Size: 128
Depends: cydia
Priority: Standard
Maintainer: iThemeSky <iThemeSky@gmail.com>
Author: iThemeSky <iThemeSky@gmail.com>
Section: iThemeSky
Architecture: iphoneos-arm
Description: Free iPhone Themes, Best iPhone 4 Themes, iPad Themes, iPhone Themes, Best Winterboard Themes Download.
HomePage: Free iPhone Themes, Best iPhone 4S Themes, iPhone 4 Themes, iPad 2 Themes, iPad Themes, Winterboard Themes, Dreamboard Themes Download.
Sponsor: iThemeSky.com <http://www.iThemeSky.com>

========================================



content of "Packages" file in my cydia source
========================================

Package: com.iThemeSky.iThemeSky
Version: 1.0
Section: iThemeSky
Maintainer: iThemeSky
Architecture: iphoneos-arm
Filename: deb//iThemeSky.deb
Size: 126864
MD5sum: 74374004addd21751e211fcb396d5124
Description: Free iPhone Themes, Best iPhone 4 Themes, iPad Themes, iPhone Themes, Best Winterboard Themes Download.
Name: iThemeSky
Author: iThemeSky dev team <iThemeSky@gmail.com>
Homepage: Free iPhone Themes, Best iPhone 4S Themes, iPhone 4 Themes, iPad 2 Themes, iPad Themes, Winterboard Themes, Dreamboard Themes Download.
Icon: http://update.iThemeSky.com/deb/icon@2x.png
========================================


Look forward to your help, thank you