I jst drop my ca in 2011...

CA Final registration/revalidation is valid for a period of 5 years.

At present, the last attempt for old syllabus final course is Nov-2020, unless extended further.

So, first of all if you want to give exam under the old syllabus, you have to revalidate your registration. Fees will be Rs. 500/- and process is online now.

If you decide to not continue your studies under old syllabus and wish to continue under new scheme, then you have to convert the registration into new scheme, instead of revalidation.

Conversion fees is Rs. 1000. If you want to give exam under new scheme in May-2020, then cut off date for conversion is on/before 01.02.2020.