diff --git a/CMakeLists.txt b/CMakeLists.txt
index a7765f0e..5482b0ae 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -21,6 +21,7 @@ target_compile_definitions(psp_module_api INTERFACE
 target_include_directories(psp_module_api INTERFACE
     fsw/inc         # public API
     fsw/shared/inc  # all PSP shared headers
+    fsw/${CFE_PSP_TARGETNAME}/inc # all impl headers
     ${CFE_SOURCE_DIR}/cmake/target/inc    # for sysconfig
     $<TARGET_PROPERTY:osal,INTERFACE_INCLUDE_DIRECTORIES>  # use headers from OSAL
 )
diff --git a/README.md b/README.md
index 1da825a0..4d0f2dca 100644
--- a/README.md
+++ b/README.md
@@ -9,7 +9,12 @@ This is a collection of APIs abstracting platform specific functionality to be l
 
 ## Version History
 
-### Development Build: 1.5.0-rc1+dev76
+### Development Build: v1.5.0-rc1+dev80
+
+- HOTFIX 20210312, updates to work with older CMake
+- See <https://github.com/nasa/PSP/pull/267>
+
+### Development Build: v1.5.0-rc1+dev76
 
 - Fix #246, remove unused code.
 - Fix #254, use CMake to publish interface details
diff --git a/fsw/mcp750-vxworks/CMakeLists.txt b/fsw/mcp750-vxworks/CMakeLists.txt
index 1cfb39ec..1b6972fa 100644
--- a/fsw/mcp750-vxworks/CMakeLists.txt
+++ b/fsw/mcp750-vxworks/CMakeLists.txt
@@ -18,5 +18,12 @@ add_library(psp-${CFE_PSP_TARGETNAME}-impl OBJECT
     src/cfe_psp_timer.c
     src/cfe_psp_watchdog.c
 )
-target_include_directories(psp-${CFE_PSP_TARGETNAME}-impl PRIVATE inc)
-target_link_libraries(psp-${CFE_PSP_TARGETNAME}-impl PRIVATE psp_module_api)
+target_compile_definitions(psp-${CFE_SYSTEM_PSPNAME}-impl PRIVATE
+    $<TARGET_PROPERTY:psp_module_api,INTERFACE_COMPILE_DEFINITIONS>
+)
+
+target_include_directories(psp-${CFE_PSP_TARGETNAME}-impl PRIVATE 
+    inc
+    $<TARGET_PROPERTY:psp_module_api,INTERFACE_INCLUDE_DIRECTORIES>
+)
+
diff --git a/fsw/mcp750-vxworks/inc/psp_version.h b/fsw/mcp750-vxworks/inc/psp_version.h
index d48abdbb..81a169df 100644
--- a/fsw/mcp750-vxworks/inc/psp_version.h
+++ b/fsw/mcp750-vxworks/inc/psp_version.h
@@ -29,7 +29,7 @@
 /*
  * Development Build Macro Definitions
  */
-#define CFE_PSP_IMPL_BUILD_NUMBER   76
+#define CFE_PSP_IMPL_BUILD_NUMBER   80
 #define CFE_PSP_IMPL_BUILD_BASELINE "v1.5.0-rc1"
 
 /*
diff --git a/fsw/pc-linux/CMakeLists.txt b/fsw/pc-linux/CMakeLists.txt
index 19344b36..5918683d 100644
--- a/fsw/pc-linux/CMakeLists.txt
+++ b/fsw/pc-linux/CMakeLists.txt
@@ -23,7 +23,11 @@ add_library(psp-${CFE_PSP_TARGETNAME}-impl OBJECT
 # Code outside the pc-linux PSP should _not_ depend on this.
 target_compile_definitions(psp-${CFE_SYSTEM_PSPNAME}-impl PRIVATE
     _GNU_SOURCE
+    $<TARGET_PROPERTY:psp_module_api,INTERFACE_COMPILE_DEFINITIONS>
+)
+
+target_include_directories(psp-${CFE_PSP_TARGETNAME}-impl PRIVATE 
+    inc
+    $<TARGET_PROPERTY:psp_module_api,INTERFACE_INCLUDE_DIRECTORIES>
 )
 
-target_include_directories(psp-${CFE_PSP_TARGETNAME}-impl PRIVATE inc)
-target_link_libraries(psp-${CFE_PSP_TARGETNAME}-impl PRIVATE psp_module_api)
diff --git a/fsw/pc-linux/inc/psp_version.h b/fsw/pc-linux/inc/psp_version.h
index 3c73e607..ec0ced14 100644
--- a/fsw/pc-linux/inc/psp_version.h
+++ b/fsw/pc-linux/inc/psp_version.h
@@ -29,7 +29,7 @@
 /*
  * Development Build Macro Definitions
  */
-#define CFE_PSP_IMPL_BUILD_NUMBER   76
+#define CFE_PSP_IMPL_BUILD_NUMBER   80
 #define CFE_PSP_IMPL_BUILD_BASELINE "v1.5.0-rc1"
 
 /*
diff --git a/fsw/pc-rtems/CMakeLists.txt b/fsw/pc-rtems/CMakeLists.txt
index fb736cf0..4d55fffc 100644
--- a/fsw/pc-rtems/CMakeLists.txt
+++ b/fsw/pc-rtems/CMakeLists.txt
@@ -18,6 +18,14 @@ add_library(psp-${CFE_PSP_TARGETNAME}-impl OBJECT
     src/cfe_psp_timer.c
     src/cfe_psp_watchdog.c
 )
-target_include_directories(psp-${CFE_PSP_TARGETNAME}-impl PRIVATE inc)
-target_link_libraries(psp-${CFE_PSP_TARGETNAME}-impl PRIVATE psp_module_api)
+
+target_compile_definitions(psp-${CFE_SYSTEM_PSPNAME}-impl PRIVATE
+    $<TARGET_PROPERTY:psp_module_api,INTERFACE_COMPILE_DEFINITIONS>
+)
+
+target_include_directories(psp-${CFE_PSP_TARGETNAME}-impl PRIVATE 
+    inc
+    $<TARGET_PROPERTY:psp_module_api,INTERFACE_INCLUDE_DIRECTORIES>
+)
+
 
diff --git a/fsw/pc-rtems/inc/psp_version.h b/fsw/pc-rtems/inc/psp_version.h
index 09c40e4d..376e4efc 100644
--- a/fsw/pc-rtems/inc/psp_version.h
+++ b/fsw/pc-rtems/inc/psp_version.h
@@ -29,7 +29,7 @@
 /*
  * Development Build Macro Definitions
  */
-#define CFE_PSP_IMPL_BUILD_NUMBER   76
+#define CFE_PSP_IMPL_BUILD_NUMBER   80
 #define CFE_PSP_IMPL_BUILD_BASELINE "v1.5.0-rc1"
 
 /*
diff --git a/fsw/shared/CMakeLists.txt b/fsw/shared/CMakeLists.txt
index 0f9ab127..05806af0 100644
--- a/fsw/shared/CMakeLists.txt
+++ b/fsw/shared/CMakeLists.txt
@@ -23,7 +23,11 @@ add_library(psp-${CFE_PSP_TARGETNAME}-shared OBJECT
     src/cfe_psp_ram.c
 )
 
+target_compile_definitions(psp-${CFE_SYSTEM_PSPNAME}-shared PRIVATE
+    $<TARGET_PROPERTY:psp_module_api,INTERFACE_COMPILE_DEFINITIONS>
+)
+
 target_include_directories(psp-${CFE_PSP_TARGETNAME}-shared PRIVATE 
-    $<TARGET_PROPERTY:psp-${CFE_PSP_TARGETNAME}-impl,INCLUDE_DIRECTORIES>
+    $<TARGET_PROPERTY:psp_module_api,INTERFACE_INCLUDE_DIRECTORIES>
 )
-target_link_libraries(psp-${CFE_PSP_TARGETNAME}-shared PRIVATE psp_module_api)
+