In libraries, there is something like a war of opinions about library software in the last couple of years: some (in particular library management) prefer the licensing of commercial software products with strict business models, others (n particular library IT) participate in community driven open source solutions. Probably, the truth lies somewhere in between, which means that standards, interfaces, and interoperability play a more and more imortant role in the business of library IT, and thus have to be open. At the same time, monolithic commercial software solutions implying vendor lock-ins emerge, promising all-in-one one-stop-shop solutions, obstructing an objective debate between library management and IT staff. The talk intends to give some experiental report on the past, tries to answer questions and reasons of the present, and gives some vision (and hopefully discussion) on the future of library IT.