When you deploy or update an instance of Acumatica ERP in the Acumatica ERP Configuration wizard, make sure the Use Modern UI as Default check box is selected (the default state), as shown below.
appSettings
<add key="EnableSiteMapSwitchUI" value="False" />
If you switch a form’s UI by using the methods described below, the form’s UI will be switched for all users. Thus, this capability is not provided to all users. Only users with the Edit level of access rights to the Site Map (SM200520) form can switch the UI of a form.
While viewing a form in the Modern UI, you can click the Settings button on the form title bar and then Switch to Classic UI to switch the form to the Classic UI.
The Switch to Modern UI command is available for only the forms that have been migrated to the Modern UI.
To specify the user interface for all forms, use the Default UI setting on the Site Preferences (SM200505) form. It defines the UI to be used by default (Modern UI or Classic UI) for all users of the current tenant.
The form will use the interface specified as the default UI, if the form supports the selected UI.
You can use the Site Map (SM200520) form to specify the default UI to be displayed for any number of forms.
To cause a form to be displayed in the Modern UI or the Classic UI, you select Modern, Classic, or Default in the UI column of the row that corresponds to the form, as shown in the following screenshot.