Does CVE-2026-55944 (NAV 2018 deserialization RCE) affect NAV 2017?

CVE-2026-55944 (published July 14, 2026, severity 9.8 out of 10) is a security flaw affecting Microsoft Dynamics NAV 2018, allowing a remote attacker to take over a system without needing to log in first. We support a client running Dynamics NAV 2017 and need to know if NAV 2017 has the same flaw, since NAV 2017 isn't mentioned in any advisory or list of affected products I've found. Questions: 1. Did Microsoft test NAV 2017 as part of investigating this issue? 2. Can Microsoft confirm NAV 2017 is safe, or is it just not covered by this particular alert? 3. If NAV 2017 wasn't tested, are there known differences between NAV 2017 and NAV 2018 that would make NAV 2017 immune to this specific problem? I've spent three weeks trying to get an answer through a paid Microsoft support incident but haven't been able to get through to anyone due to an unrelated account access problem on Microsoft's side.