Short answer is "no".
Agile is an add-on for JIRA 4.something through to 6.last. (Before that, it was Greenhopper). For JIRA 7, the functionality is now provided by the JIRA Software application. The code has changed a lot, and I've no idea how much Greenhopper original code has made it into Software. On the surface, you can think of the changes as being rebranding, but under the hood, the changes are massive.
Older versions, while deprecated and not maintained, are still products. To use the analogy of software most people will know, think about Windows. None of the old versions of that are "free". They're unsupported, unused, deprecated, and have no development going into them, but technically, you still have to buy them if you want to use them.
Atlassian's licence model is a lot more fair to users than Microsoft's though. A licence entitles you to use any version of the product released before the end of the licence.
Seems as though that last version of JIRA Agile was 6.7. JIRA agile now seems to be JIRA Software:
The Atlassian JIRA Software team is proud to announce the release of JIRA Software 7.1.0.
This release contains major updates and fixes, focused on providing purpose-built experience for software teams. Upgrading from JIRA or JIRA+JIRA Agile to JIRA Software is free for all customers with active JIRA Software maintenance.
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