MILWAUKEE — Struggling retailer Bon Ton Stores has put together a turnaround plan focused on closing underperforming stores, providing more sought-after merchandise, improving its marketing and increasing online-related sales by 50 percent in the next two years.

The plan to bolster the business of Bon Ton, which is the parent company of Boston Store, Younkers and other department stores, is projected to increase revenue by almost 5 percent by the end of 2020.

The turnaround plan was disclosed Monday in connection with a debt restructuring that Bon Ton is working on with its debt holders.

Bon Ton, which has dual headquarters in Wisconsin and York, Pa., has been unprofitable for the last six years and recently missed a $14 million debt payment.

The turnaround plan states there is “a clear opportunity to enhance Bon Ton’s performance” over the next two years.

Bon Ton already has said it expects to close at least 40 stores in 2018. The turnaround plan puts the number at 42, and potentially three more, including a clearance center. The stores marked to close typically have had weak financial performance and are located in dying malls, the plan says. The plan does not identify the stores likely to close.

The Bon Ton at Clearview Mall closed in October 2014. It opened in 1982.

Bon Ton has 260 stores in the U.S., including furniture galleries and clearance centers, in addition to department stores.

Department stores located in shopping malls — as most Bon Ton stores are — have been hit particularly hard by the growth of online retailers such as Amazon.com and the trend of declining visits to malls.

Through the first three quarters of 2017, Bon Ton lost $135.4 million.