Ahead of its upcoming initial public offering, social gaming giant Zynga has accepted a settlement in a copyright infringement lawsuit it brought against Brazilian social game maker Vostu, which it had accused of blatantly copying some of its most popular games.

As part of the settlement, Vostu will make changes to four of its games and pay an undisclosed sum to Zynga. Vostu will also drop a counterclaim it had made against Zynga.”The parties are pleased to have settled their disputes and to now put these matters behind them,” the companies said in a joint statement.

A Vostu spokesperson declined to comment further on the details of the settlement or which of its games would be changed under the terms of the agreement.

Allegations of game copying are widespread in the social and casual game industries, with popular titles quickly spawning copycats that slightly tweak the concept or gameplay in some small way. Zynga’s own FarmVille is widely considered to be a much more successful copy of Slashkey’s  previously released social game Farm Town.

But Zynga’s lawsuit, originally filed in June, accused Vostu of taking more than simple inspiration from Zynga’s titles by copying games including FarmVille, Zynga Poker, PetVille, Cafe World, and CityVille right down to key gameplay features and even structural glitches found in the titles.

At the time, Vostu called the lawsuit “frivolous” and said its titles were “chock full of original content” that had been “individually created.”

The settlement comes at a crucial time for Zynga, which will finally offer its long-mulled IPO starting December 15, though at a price much lower than previous expectations.

Vostu, which has offices in New York, Sao Paolo and Buenos Aires is backed by $46 million raised last year by Accel Partners and Tiger Global Management, among others. The company claims over 25 percent of all internet-connected Brazilians play its games, including recently launched soccer sim GolMania.