It’s been a rocky year at Success Academy High School for the Liberal Arts in Manhattan.

Students at the charter network’s first high school have protested the school’s discipline policies and dress code, which once barred students from wearing scarves with African prints. They started a petition to push back against hours of work assigned each week over the summer.

And last week, the Wall Street Journal reported that just 20 of the school’s 67 teachers and administrators will be returning when classes start this fall.

Following that latest sign of discord, the charter network is set to convene a meeting this Wednesday to discuss “any concerns” parents might have regarding turnover, summer homework, and promotion standards, according to a letter sent to the school’s parents and which was obtained by Chalkbeat.

“I know it can be hard on students when a favorite teacher leaves, but our number one priority is providing our scholars with the same high quality education that we’ve given them since elementary school,” Success CEO Eva Moskowitz wrote.

Concerns about Success’ first high school come at a delicate moment, as Moskowitz is trying to double the number of schools in what is already the city’s largest charter network. The network has shown that it can blow past district averages on state tests at its elementary and middle schools, but has also been criticized for deploying draconian discipline practices and appeared to struggle at times to adapt the model to its high school.

Its first senior class graduated just 16 students this summer, raising questions about how the model can be quickly expanded if the network loses so many students on their path to a diploma without adding students in later grades.

In her letter to parents, Moskowitz addressed some of the issues students raised during the school year, including concerns about summer homework, and a policy of forcing students to repeat a grade if they struggle with coursework.

“I understand that it can be hard for our scholars to meet the high expectations we set,” Moskowitz wrote, referring to those policies, “but those standards must be high to ensure that our scholars not only get into good colleges but succeed there.”

You can read the full letter here:

Updated (7/31): After this story was published, a KIPP spokeswoman said the statistics about the charter network included in Moskowitz’s letter are not up to date. The most recent statistics can be found here