Hi,

Try like below code.

from odoo.tools import date_utils

def max_date(self):
    today = fields.date.today()
    next_month = date_utils.add(today, months=1)
    date_max = date_utils.end_of(next_month , "month")

Regards

You can try following code to get next month's last day:

import datetime

from dateutil.relativedelta import relativedelta

next_month_max_day =((datetime.datetime.today().date() + relativedelta(months=+1,day=31))).day

import calendar
date_now = datetime.today()
day_max = calendar.monthrange(date_now.year, date_now.month +1 )[1]  # return tuple( 1.st day, number of days)

hope it helps

Try this,

from dateutil.relativedelta import relativedelta
from datetime import datetime
next_month = datetime.today() + relativedelta(months=1)
date_max=next_month.max.day