** Shares of Infomedia IFM.AX fall as much as 7.2% to A$1.355, posting their biggest intraday pct loss since Sept. 13
** Software firm revises down revenue guidance to A$142 mln-A$149 mln ($93.48 mln-$98.09 mln) from A$144 mln-A$154 mln for fiscal 2025
** Attributes change to loss of existing customers of about A$4 mln in October and delays in dealer management system integration due to low availability of IT resources, among others
** Says still expects stronger second-half performance
** Stock down 3.5% YTD
($1 = 1.5191 Australian dollars)
(Reporting by Nikita Maria Jino in Bengaluru)
((Nikita.Jino@thomsonreuters.com;))