SSL R3 .pem validity

hello my question is R3 is based on ISRG X1 when i download the .pem file from R3 this means that this root certificate is valid untill 2035? kindly help me in this matter i am confused. when i click on my certificate deatils in morzrilla fox ...i see 3 certficates my domain, R3 , and DST Root CA X3.. which one should i download i am confused.... because R3 and DST Root CA X3 says validity untill Oct-2021... but i am told R3 is valid untill 2035.... all i can download is .pem file..

Response will be highly appreciated

5 posts were merged into an existing topic: Root CA for IOT