The suit, filed in federal court in the District of Delaware, charges Lotus with copyright infringement, unfair competition, breach of contract, misappropriation of trade secrets, and unjust enrichment and conversion. Verity (VRTY) is seeking an injunction against Lotus along with damages.
Lotus officials could not be immediately reached for contact.
The suit claims that Lotus violated Verity copyrights for advanced document viewing and retrieval and search and index filters.
Although Lotus has a license agreement with Verity, Verity officials claim those technologies are "far outside the scope permitted by its contract."
"Lotus does not have the right to those advanced features and products, or to make available to consumers any of the features allowing for searches outside of the Lotus Notes environment," Verity officials said in a press release.
Lotus has announced that Version 5.0 of Notes, due out by the end of this year, will allow users to search across databases and on the Web.
In an interview with PC Week last month, Lotus President Jeff Papows said that the new version will let users "search across the Web or the Internet for a category of information with the same kind of seamlessness that you'd search across a Notes database. We can bring it back and, importantly, filter it, categorize it, rank it."