If you have flexibility about when features can be released then you can do agile.
I wish the agile and scrum evangelists were honest about this.
The most agile company I ever worked for never talked about scrum or agile. We just asked customers what they wanted and integrated it into the product. When features were ready we released them. There was no roadmap or timetable. Sometimes customers would ask us when things will be ready, we always pushed back on giving dates.