First, the relationship syntax is not correct for UML $2\mathrm{.}0$ if this is a class diagram. We cannot see how the classes relate as a result. Thus, I would work on this.

Second, attribute types need to be correct. Add attributes where transactions and other historical actions are needed for subsequent methods in the application.

Third, often, we need attributes like keys for an array. They are missing. Please add attributes as a result for the full features needed in the new app.