This is a legacy-only release. It includes the original, unmodified AASTeX 6.3.1 files published to the AAS Journals website on March 1, 2021. Users are advised that these files should be considered deprecated by the current v6.3+ and v7+ versions. Contributors to v6.3+ via GitHub include, not including by name individuals who contributed numerous issues reported to us or sent by email to AASTeX support Mars Buttfield-Addison Alfred de Wijn Hans Moritz Günther Adam Jacobs Tim Jenness Katrin Leinweber Chris Lowder Matt Pitkin https://github.com/bezthomas 

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