The eligibility will remain the same in reference to minimum age limit and the aggregate required. Regarding the upper age limit and cap on no.of attempts, the matter is still pending in the Supreme Court. Regarding the syllabus, the MHRD did announce the JEE Mains and NEET syllabus for 2021 will be reduced and revised. While MHRD did not mention the topics that might be retained or deleted, CBSE has released the official syllabus for Class 11 and Class 12 at its official website. You can check the revised syllabus at: http://cbseacademic.nic.in/revisedcurriculum_2021.html . For now, you should focus on these topics and stick to NCERT books. This should be the way because you do not want to study and spend time on those topics that might not be included in the exam syllabus. Sticking to NCERT atleast until MHRD or NTA releases the official syllabus will help you in saving money and  not spending on not yet updated books. Also practise atleast one mock test a week to get a hang of the exam pattern and time management.For now atleast until the new syllabus is released, this should be your preparation strategy.