At https://fedoraproject.org/wiki/Packaging/Tcl I read Both arch-specific and noarch Tcl extensions MUST use Requires: tcl(abi) = 8.5 which seems more than a little bizarre when every other part of the page tells you that you MUST avoid putting hard-wired Tcl version number dependencies into your specfile. And it also tells you exactly how to extract the Tcl version dynamically. So why isn't this a better solution? Requires: tcl(abi) = %{tcl_version} regards, tom lane