Responding to objections from activists and Boston officials, WS Development has revamped its plans to develop 12.5 acres of Seaport District real estate to include more park space and two performing arts facilities.

WS said it has agreed to extend the operation of the District Hall tech hub for at least 10 years and will create another incubator space for small businesses.

WS bought the surface parking lots from Seaport Square master developer Boston Global Investors in 2015 for $359 million. This spring, it submitted changes to the previously approved plans for the area, some of the last development sites in the heart of the booming South Boston waterfront.

WS sought to increase office space by 1.7 million square feet and add 700 more residential units. Open space advocates criticized the elimination of a 1.3-acre park as part of a new layout and dropping of plans for a 200,000-square-foot performing arts center in favor of smaller spaces in multiple buildings.

Boston Planning and Development Agency staff objected to some of the changes, and asked WS to study a performing arts space with capacity for 800 people, a facility for theater, music and dance with 500-person capacity and black box theaters for audiences of 150 and 100 people. WS executives said they would go back to the drawing board.

The revisions, filed with the BPDA today, call for a 600-seat Seaport Performing Arts Center (SeaPAC), a 150-seat community theater, 1.5 acres of park space on the “L” blocks, and expansion of the Seaport Common park to nearly 1 acre.

As mitigation, WS said it would provide a $2.5 million operating subsidy over 10 years to enhance water transportation service to the transit-challenged Seaport or upgrades to MBTA Silver Line capacity.

To make room for the changes, a retail building on Seaport Boulevard next to District Hall would be reduced by 80,000 square feet.