diff --git a/src/mpsd_software_manager/mpsd_software.py b/src/mpsd_software_manager/mpsd_software.py
index 7405e35eddb01ff53d160776fb65717966eb440a..45ab731f121ff1a28dd7a267eb446623440f5d75 100755
--- a/src/mpsd_software_manager/mpsd_software.py
+++ b/src/mpsd_software_manager/mpsd_software.py
@@ -142,7 +142,7 @@ def create_log_file_names(
     microarch: str,
     action: str,
     date: str = call_date_iso,
-    package_set: str = None,
+    package_set: Union[str, None] = None,
 ) -> Union[str, None]:
     """Create log file names.
 
@@ -194,7 +194,7 @@ def create_log_file_names(
 
 
 def get_log_file_path(
-    mpsd_release: str, cmd: str, root_dir: Path, package_set: str = None
+    mpsd_release: str, cmd: str, root_dir: Path, package_set: Union[str, None] = None
 ) -> Union[Path, None]:
     """Get installer log file path.
 
@@ -583,7 +583,9 @@ def run(*args, counter=[0], **kwargs):
     return process
 
 
-def record_script_execution_summary(root_dir: str, msg: str = None, **kwargs) -> None:
+def record_script_execution_summary(
+    root_dir: Path, msg: Union[str, None] = None, **kwargs
+) -> None:
     """Log the command used to build the package_set.
 
     It also logs information about the spack-environments branch and commit hash,
@@ -1025,7 +1027,7 @@ def start_new_environment(release, from_release, target_dir):
     raise NotImplementedError(msg)
 
 
-def environment_status(mpsd_release: str, root_dir: Union[str, Path]) -> dict:
+def environment_status(mpsd_release: str, root_dir: Path) -> Union[dict, None]:
     """Show status of release in installation.
 
     Parameters
@@ -1042,6 +1044,7 @@ def environment_status(mpsd_release: str, root_dir: Union[str, Path]) -> dict:
     toolchain_map : dict
         A dictionary containing available microarchitectures as keys and
         a list of available package_sets as values for each microarchitecture.
+        If the release is not installed/found, None is returned.
 
         Note: only toolchains can be reported at the moment (i.e. package_sets
         such as global and global_generic are missing, even if installed).