diff --git a/.python-version b/.python-version
deleted file mode 100644
index a0fc9e07c..000000000
--- a/.python-version
+++ /dev/null
@@ -1 +0,0 @@
-3.7.8
diff --git a/stm32-modules/heater-shaker/src/CMakeLists.txt b/stm32-modules/heater-shaker/src/CMakeLists.txt
index 5d008a065..0cd707bc4 100644
--- a/stm32-modules/heater-shaker/src/CMakeLists.txt
+++ b/stm32-modules/heater-shaker/src/CMakeLists.txt
@@ -15,7 +15,7 @@ if (NOT TAGNAME)
 endif()
 
 string(REGEX MATCH "@.*$" PREPENDED_VERSION ${TAGNAME})
-string(SUBSTRING ${PREPENDED_VERSION} 1 -l VERSION)
+string(SUBSTRING "${PREPENDED_VERSION}" 1 -1 VERSION)
 if (NOT VERSION)
   set(VERSION "(dev)")
 endif()