Hello team,
I have seen Windows XP support has been dropped as of 3.2. Is that because of lack of MS support for that OS? If that´s the point, there is an OS which is being developed to substitute XP/2003 , it´s Open Source and you may still support it!
check https://www.reactos.org
Thank you in advance!
P.S.: Yes, i contribute translating and testing that OS 
I think the problem was related to a point at which there was a failure to compile VS2019 with legacy 32bit systems. (unsure at which commit it failed)
For hints to restore XP directives were only removed 2 weeks ago in https://github.com/sumatrapdfreader/sumatrapdf/commit/28bd54bd66adb019176eb48c03518ae65f217799
If you can try compiling current builds on reactos and succeed then you may be on to a winner as the native PDF application.
well a 64-bit ReactOS version is ongoing as well
you could try the 32bit pre-release portable https://www.sumatrapdfreader.org/prerelease.html and report any failings
Just an update, I was not able to run ReactOS on my working hardware due to atom or celeron issues.
What I did Note was that earlier versions of ReactOS included “SmartPDF” which was supposedly a variant of the earlier Poppler based SumatraPDF, however that was dropped from ReactOS in May 2008.
Many users have said in the forums they could run SumatraPDF without too many problems from 2007 up to the 2016 x32 version 3.1.2 so I would be testing that first.
Most ReactOS bug reports for SumatraPDF are “resolved/wont fix” there is only the odd open one for fullscreen mode where SumatraPDF is not fixed as "OnTop of the toolbar. However that can also be seen in Windows 10 with current release, where “Always on Top” apps or the Toolbar are allowed to override SumatraPDF.
ReactOS x64 is Bleeding Edge Alpha Alpha so dont expect SumatraPDF 3.2.# x64 to be supported by ReactOS for possibly some time.
It would be beneficial if someone running newest versions of ReactOS could test a current SumatraPDF Pre-Release x32 build and report their findings.
This list https://reactos.org/wiki/User:Matthiasbasler#Office is now out of date but reports 3.1.1 ran well. The current recommended Rapps version is 3.1.2 as downloaded by https://github.com/reactos/rapps-db/blob/master/sumatrapdf.txt