diff --git a/Dockerfile b/Dockerfile
index 53aad9f..3e20f62 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -55,5 +55,5 @@ RUN eval "$(micromamba shell hook --shell bash)" && python -m pip install -e .[d
 # Main
 #####
 FROM base as main
-USER $MAMBA_USER
-RUN eval "$(micromamba shell hook --shell bash)" && python -m pip install .[dev]
\ No newline at end of file
+RUN eval "$(micromamba shell hook --shell bash)" && python -m pip install .[dev]
+USER $MAMBA_USER
\ No newline at end of file
diff --git a/anglerfish/anglerfish.py b/anglerfish/anglerfish.py
index 5a2014a..006c158 100755
--- a/anglerfish/anglerfish.py
+++ b/anglerfish/anglerfish.py
@@ -128,7 +128,7 @@ def run_demux(args):
                     adaptors_sorted[key], fragments, args.max_distance, **rev
                 )
                 flipped[flip] = (rc_matches, rc_no_matches, len(rc_matches))
-            best_flip = max(zip(flipped.values(), flipped.keys()))[1]
+            best_flip = max(flipped, key=lambda k: flipped[k][2])
 
             # There are no barcode flips with unambiguously more matches, so we abort
             if (
diff --git a/setup.py b/setup.py
index 3cf86dd..3102168 100644
--- a/setup.py
+++ b/setup.py
@@ -17,7 +17,7 @@
 this_directory = Path(__file__).parent
 long_description = (this_directory / "README.md").read_text()
 
-version = "0.6.1-dev"
+version = "0.6.1"
 
 setup(
     name="bio-anglerfish",