Note: Autodesk no longer supports offline activation for 2021 products and later. If you have a perpetual license, you can activate your software by going online only once. After you activate online, you can continue to use 2021 software and later offline. This change doesn’t apply to subscription network licenses or previous versions that you already activated offline. You can continue to use them as before.
One of the benefits of subscriptions and maintenance plans is access to previous versions of your software. Support is available for all current versions of Autodesk software plus some previous versions, typically three versions back. To be eligible for support, the Autodesk software must run on vendor-supported operating systems. If a vendor discontinues support for an operating system, we also discontinue support for Autodesk products running on that operating system, whether or not the products are among the eligible previous versions.
If a previous version isn’t listed, support isn’t available. To avoid downtime, upgrade to a supported version before a previous version reaches the end of support. Customers who have maintained an active maintenance or subscription plan without lapse can continue to use a previously installed and activated version, even if it has reached end of support. If you have a perpetual license for a version that has reached end of support, you still have rights to use the license for as long as you want.
However, for unsupported versions, you can’t get a new activation code to reactivate that version for any device. We also will not release software updates or hotfixes for versions that have reached end of support.
Upgrade to a supported version
Note: Visit http://www.store.cadgroup.com.au/ to subscribe to the latest version.
Please Refer to Autodesk for current outline. Source: https://knowledge.autodesk.com/customer-service/account-management/users-software/previous-versions/previous-version-support-policy