Hello,
You will fill it as 2019 only and write appeared in the form and calculate your mark including the subjects you have improved. There won't be any problem as you will write as appeared for the improvement section.
You can visit the site :- https://engineering.careers360.com/articles/how-to-fill-jee-main-application-form
In above article you will get step by step guidance for filling the form.
If you have done any mistake then there will dates released for correction. You can make corrections at that time. Before correcting anything make sure you are giving all details accurately else the board will reject the form if not you will get rejected during counseling if you don't provide documents accordingly.
Hope it helps!

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