Software vendors regularly make announcements that certain versions of software will no longer be supported after a particular date. Such dates are known as End-of-Life. After the End-of-Life, software is no longer supported and can therefore not be considered to be secure. The Dutch National Cyber Security Centre advises to update systems after the announcement as soon as possible.
Read NCSC factsheet here - https://www.ncsc.nl/binaries/content/documents/ncsc-en/services/expertise-advice/knowledge-sharing/factsheets/software-has-an-expiry-date/1/Factsheet_Software_has_an_expiry_date.pdf