More than 23,500 children in Northern Ireland find out which post-primary school they will transfer to on Saturday.
For the first time in decades, grammar schools have not used transfer tests to decide which pupils to admit.
Both test providers cancelled them due to disruption to schools caused by the coronavirus pandemic.
As a result, almost all grammars are not using any academic criteria to select pupils for September 2021.
BBC News NI understands that a number of grammar schools are significantly oversubscribed.
In a separate process, many children with Special Educational Needs (SEN) will also find out which school they will move to.
There are 193 post-primary schools in Northern Ireland – 66 grammars and 127 non-grammars.
Parents of Primary Seven pupils were encouraged to name at least four schools they wanted their children to transfer to, in order of preference.
For the first time, the process managed through the Education Authority (EA) has been fully online and pupils also find out which school they are going to online rather than by letter.
However, individual boards of governors make the decision on which pupils their school will admit based on their criteria.
There were 16,257 entrants in total for the AQE and Post-Primary Transfer Consortium (PPTC) tests when they most recently took place in 2019 – although some children sit both.
Non-selective schools use relatively similar criteria each year, but with no transfer tests in 2020-21 grammars have had to draw up alternative criteria to those they would have used previously.
In a statement the EA said that 23,535 children were due to transfer to post-primary in September.
They said almost 85% of pupils would get a place in their first-preference school, while more than 98% would be placed in a school that was listed among their choices.
The EA will run a telephone helpdesk on Saturday 12 June from 0900 to 1700 and it will reopen again on Monday.
The helpdesk number is 028 9598 5595.
“Work is also under way to secure placements for children with a statement of special educational needs, which is a separate process,” the EA said.
“The majority of parents will have already received their child’s amended statement naming their placement for September.
“Where places have not been confirmed by 14 June 2021, our Special Educational Needs (SEN) Team will contact parents directly to update them on their individual consultation process.”
There is a separate SEN Helpline run by the EA on 028 9598 5960.