Here are the recent changes to the packaging guidelines.
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The use of rich (or Boolean) dependencies is now OK for F23+.
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https://fedoraproject.org/wiki/Packaging:Guidelines#Rich.2FBoolean_depend...
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https://fedorahosted.org/fpc/ticket/593
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The ban on the use of the %systemd_requires macro has been lifted.
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https://fedoraproject.org/wiki/Packaging:Scriptlets#Systemd
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https://fedorahosted.org/fpc/ticket/600
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The mono guidelines were modified to require that packages limit
themselves via ExclusiveArch: to architectures which actually support
mono.
*
https://fedoraproject.org/wiki/Packaging:Mono
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https://fedorahosted.org/fpc/ticket/602