HI  jordan,

You want to generate year in sequence number so you should try below code,

•    This is  Sequence.xml file.

• And if you want to change sequence number in sale module than you have to override create method of sale module by using super method. 

class SaleOrder(models.Model):

_inherit = 'sale.order'

@api.model

def create(self, vals):

 vals['name'] = self.env['ir.sequence'].sudo().next_by_code(

                        'sale.order') or '/'

    res = super(SaleOrder, self).create(vals)

    return res

You can add above code  into your .py file.  

 I hope this is helpful to you.

 Thanks & Regards,

 Email: odoo@devintellecs.com

 Skype: devintelle