 In the months following this release , development shifted from Windows Mobile to its successor Windows Phone . As such no major upgrades were planned or released , although three minor updates ; 6 @.@ 5 @.@ 1 , 6 @.@ 5 @.@ 3 and 6 @.@ 5 @.@ 5 ; were made to satisfy consumers during the transition period . 6 @.@ 5 @.@ 1 brings larger user interface elements , including icon based soft buttons ( rather than text based ) , an updated contacts app , native support for A @-@ GPS , improved threaded text messaging , and performance improvements . It was unofficially ported to several Windows Mobile phones . 
