Like the other manufacturers, Huawei also has an EOL (End of Life) policy for both hardware and software. The policy is described here.
Both the hardware and the software are no longer supported by Huawei after a certain period of time. It starts with the EOM Announcement and ends with the EOL. These dates can be found for each product or software on the Huawei website - you can also check the article about all the support websites here.
Abbreviations
EOM Announcement: Huawei provides information about the EOM of a product or software. This information is 6 months before the EOM date.
EOM (End of Marketing): Huawei no longer sells the product or the software can no longer be downloaded.
EOS (End of Support) or EOL (End of Life): As of this date there is no more support from Huawei.