Yes, you're right. The oe_edit_only and oe_read_only classes are no longer available in Odoo 16. Instead, you can use the attrs attribute in the field definition to show/hide fields depending on whether the user is editing or just reading the form.

Here is an example of how you can use the attrs attribute to show/hide a field:

field_name = fields.Char(string="Field Name", readonly=True, states={'edit': [('readonly', False)]})

In this example, the readonly attribute is set to True, which means that the field is read-only by default. However, if the user is editing the form, the readonly attribute is set to False using the states attribute.

You can also use the attrs attribute to show/hide fields based on other conditions. For example, you can show/hide a field based on the value of another field:

other_field = fields.Boolean(string="Other Field")

field_name = fields.Char(string="Field Name", attrs={'invisible': [('other_field', '=', True)]})

In this example, the field_name field is hidden when the other_field field is set to True.

You can find more information about the attrs attribute in the Odoo documentation: https://www.odoo.com/documentation/16.0/reference/orm.html#field-attributes.