Send the tax return in paper

I had just received my UTR last week and I am going to apply split year for 2022-23 tax year but not prefer do it online because the fee of 3rd party software is a bit expensive for me. Therefore, may I ask am I able to send the tax return SA100 and SA109 in paper by post and will not charge me any penalty even the forms arrive HMRC after 31 January 2024? Since in the UTR letter, it mentions 'You must file your return by 31 January 2024 (or 3 months after the date of this notice, whichever is later)'. If not, can I fill the tax return online before 31 January 2024 then send the paper SA109 by post separately? Thank you.

Hi FT,
As the due date for paper returns was 31/10/23, you will be automcatically charged a late filing penalty.
You must send the whole return in the same format and cannot file online and then submit the SA109 in paper form.
Thank you.