Please do not ever try joining the new company on 18th Oct, if your last working date with your current employer is on 20th Oct. This can raise issues of dual employment which can affect your career forever, especially when it comes to background verification records in the future.
It would be better to try asking your future employer on postponing the joining date to 21st or any other date.
From India, Bengaluru
Added to the above, if you do so your current employer will close your file after disciplinary process and they will mark a later date in Oct, whereas your new employer will mark your DOJ 18th Oct,2022 for PF purpose and this will create issue in transferring /claiming PF aswell.
So make a polite request to your current employer and request for 2 days exemption if not works make the same request to your new employer to postpone your DOJ by two days.
From India, Madras
sitaramsnVery good suggestions above. It is always to better to convince the present and future employers to relieve and join. It may lead to some undesirable consequences later.
From India, Hyderabad