diff -up CTL-ctl-1.5.2/lib/IlmImfCtl/CMakeLists.txt.ilmCtl CTL-ctl-1.5.2/lib/IlmImfCtl/CMakeLists.txt
--- CTL-ctl-1.5.2/lib/IlmImfCtl/CMakeLists.txt.ilmCtl	2014-06-03 03:11:24.000000000 +0200
+++ CTL-ctl-1.5.2/lib/IlmImfCtl/CMakeLists.txt	2018-10-01 15:38:32.234325643 +0200
@@ -7,6 +7,11 @@ add_library( IlmImfCtl ${DO_SHARED}
   ImfCtlCopyFunctionArg.cpp
 )
 
+set_target_properties( IlmImfCtl PROPERTIES
+  VERSION ${CTL_VERSION}
+  SOVERSION ${CTL_VERSION}
+)
+
 target_link_libraries( IlmImfCtl IlmCtl IlmImf Iex IlmThread Half )
 
 install( FILES ImfCtlApplyTransforms.h DESTINATION include/OpenEXR )