Unfortunately windows XP is not supported by the current versions of the Qt framework, used to build Polyphone.
We can see the minimum requirements here (Polyphone has been built with Qt 5.11 and soon with 5.12) wiki.qt.io/PlatformSupport
I guess you will not like my answer but you should consider upgrading your computer to windows 10 so that you can use the latest versions of the software. Releasing an XP version of Polyphone would be too much extra work to me: the sources of the software might compile but I fear I'll have to change all the dependencies too.
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