The deadline for submitting your thesis is midnight of the day set as a deadline by the Registrar.
Before proceeding, please make sure that the electronic version of your thesis satisfies the criteria described at http://seas.elte.hu/w/studies/graduation/thesis/upload.
If you make a mistake during the submission procedure, you can restart it. In the new submission you can change anything (including the file you upload), except your neptune code, so make sure you do not get that wrong. If you get your Neptune code wrong, start again from scratch and please write a message reporting your error to help@seas.elte.hu.