diff --git a/.gitattributes b/.gitattributes
index 191ace7..25b1ef7 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -1,5 +1,10 @@
 tests/testdata/eicu_demo/dyn.parquet filter=lfs diff=lfs merge=lfs -text
 tests/testdata/eicu_demo/sta.parquet filter=lfs diff=lfs merge=lfs -text
 tests/testdata/eicu_demo/hospital.parquet filter=lfs diff=lfs merge=lfs -text
+tests/testdata/eicu_demo/features.parquet filter=lfs diff=lfs merge=lfs -text
 tests/testdata/mimic_demo/dyn.parquet filter=lfs diff=lfs merge=lfs -text
-tests/testdata/mimic_demo/sta.parquet filter=lfs diff=lfs merge=lfs -text
\ No newline at end of file
+tests/testdata/mimic_demo/sta.parquet filter=lfs diff=lfs merge=lfs -text
+tests/testdata/mimic_demo/features.parquet filter=lfs diff=lfs merge=lfs -text
+tests/testdata/miiv_demo/dyn.parquet filter=lfs diff=lfs merge=lfs -text
+tests/testdata/miiv_demo/sta.parquet filter=lfs diff=lfs merge=lfs -text
+tests/testdata/miiv_demo/features.parquet filter=lfs diff=lfs merge=lfs -text
\ No newline at end of file
diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index f166cf0..d8a1518 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -30,15 +30,29 @@ jobs:
         run: python -m pip install --no-build-isolation --no-deps --disable-pip-version-check -e .
       - name: install icd-mappings
         run: pip install icd-mappings
+      - name: Move features.parquet out of the way
+        run: |
+          mv tests/testdata/eicu_demo/features.parquet tests/testdata/eicu_demo/old_features.parquet
+          mv tests/testdata/mimic_demo-carevue/features.parquet tests/testdata/mimic_demo-carevue/old_features.parquet
+          mv tests/testdata/miiv_demo/features.parquet tests/testdata/miiv_demo/old_features.parquet
       - name: feature engineering for eicu_demo
         run: |
           python icu_features/icd_codes.py --data_dir "tests/testdata" --dataset "eicu_demo"
           python icu_features/feature_engineering.py --dataset "eicu_demo" --data_dir "tests/testdata"
-      - name: feature engineering for eicu_demo
+      - name: feature engineering for mimic_demo
         run: |
           python icu_features/split_datasets.py --data_dir "tests/testdata"
           python icu_features/icd_codes.py --data_dir "tests/testdata" --dataset "mimic_demo-carevue"
           python icu_features/feature_engineering.py --dataset "mimic_demo-carevue" --data_dir "tests/testdata"
+      - name: feature engineering for miiv_demo
+        run: |
+          python icu_features/icd_codes.py --data_dir "tests/testdata" --dataset "miiv_demo"
+          python icu_features/feature_engineering.py --dataset "miiv_demo" --data_dir "tests/testdata"
+      # - name: compare new to old features.parquet
+      #   run: |
+      #     python -c "import pyarrow.parquet as pq;old = pq.read_table('tests/testdata/eicu_demo/old_features.parquet');new = pq.read_table('tests/testdata/eicu_demo/features.parquet');assert old.equals(new)"
+      #     python -c "import pyarrow.parquet as pq;old = pq.read_table('tests/testdata/mimic_demo-carevue/old_features.parquet');new = pq.read_table('tests/testdata/mimic_demo-carevue/features.parquet');assert old.equals(new)"
+      #     python -c "import pyarrow.parquet as pq;old = pq.read_table('tests/testdata/miiv_demo/old_features.parquet');new = pq.read_table('tests/testdata/miiv_demo/features.parquet');assert old.equals(new)"
       - name: Pytest
         run: pytest tests
 
diff --git a/environment.yml b/environment.yml
index 5ed7372..4a5d8ef 100644
--- a/environment.yml
+++ b/environment.yml
@@ -3,7 +3,7 @@ channels:
   - conda-forge
   - nodefaults
 dependencies:
-  - python>=3.12
+  - python==3.12
   - setuptools
   - pip
   - click
diff --git a/tests/testdata/eicu_demo/.gitignore b/tests/testdata/eicu_demo/.gitignore
deleted file mode 100644
index c84daf3..0000000
--- a/tests/testdata/eicu_demo/.gitignore
+++ /dev/null
@@ -1 +0,0 @@
-features.parquet
\ No newline at end of file
diff --git a/tests/testdata/eicu_demo/dyn.parquet b/tests/testdata/eicu_demo/dyn.parquet
index 0e1beab..b74f634 100644
--- a/tests/testdata/eicu_demo/dyn.parquet
+++ b/tests/testdata/eicu_demo/dyn.parquet
@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:1d4cbf01a2c17dc32814fc8df3b119c676d736f4158c47c2ee88b81a2f0e8f77
-size 2252914
+oid sha256:99bf738453bdf0b054ed0e092b80d5b3e142647d095673c51fe305ed7154d22b
+size 2264514
diff --git a/tests/testdata/eicu_demo/features.parquet b/tests/testdata/eicu_demo/features.parquet
new file mode 100644
index 0000000..8e5937f
--- /dev/null
+++ b/tests/testdata/eicu_demo/features.parquet
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:dcf722ba960991684c36a79ad78d40f29b22ee0a25efdb6b5c597e51b0768269
+size 68297045
diff --git a/tests/testdata/eicu_demo/hospital.parquet b/tests/testdata/eicu_demo/hospital.parquet
index a96c583..b66ba7f 100644
--- a/tests/testdata/eicu_demo/hospital.parquet
+++ b/tests/testdata/eicu_demo/hospital.parquet
@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:203c21ace7b2d8ca0bf9882e1b530eea49b035845dbc86650f61398e76563ce3
-size 2905
+oid sha256:92a328bcfe024e39b8846aafbe30194243a9dcd7a5592461139f9427298eaaa7
+size 3224
diff --git a/tests/testdata/eicu_demo/sta.parquet b/tests/testdata/eicu_demo/sta.parquet
index 93511c9..5bb45c0 100644
--- a/tests/testdata/eicu_demo/sta.parquet
+++ b/tests/testdata/eicu_demo/sta.parquet
@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:5d86e836864335842b38e24030268bf311625d3dc9e7c8d88b14c7bf5c798cb9
-size 68334
+oid sha256:e09b7218a66eed16184d4b96241ec5991b2a492e279e62b8c4e02277cc8f0f62
+size 70005
diff --git a/tests/testdata/miiv_demo/dyn.parquet b/tests/testdata/miiv_demo/dyn.parquet
new file mode 100644
index 0000000..1b9dc4a
--- /dev/null
+++ b/tests/testdata/miiv_demo/dyn.parquet
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:80ee7cb1df0397b6f7be42fa33d11e5ba659b223e04344b3fd19cb8308c897a6
+size 385801
diff --git a/tests/testdata/miiv_demo/features.parquet b/tests/testdata/miiv_demo/features.parquet
new file mode 100644
index 0000000..7e0eb61
--- /dev/null
+++ b/tests/testdata/miiv_demo/features.parquet
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:9b5e144592f37a345a3def9cb5e2a28defeae25b285eeb88c83703de4aa2d82d
+size 9520079
diff --git a/tests/testdata/miiv_demo/sta.parquet b/tests/testdata/miiv_demo/sta.parquet
new file mode 100644
index 0000000..09a18ae
--- /dev/null
+++ b/tests/testdata/miiv_demo/sta.parquet
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:c024b1e3e23ccae52043e2c7a3e7c32d606a4e1b170ca05b32b319acd96c22ab
+size 15520
diff --git a/tests/testdata/mimic_demo-carevue/dyn.parquet b/tests/testdata/mimic_demo-carevue/dyn.parquet
new file mode 100644
index 0000000..9393a47
Binary files /dev/null and b/tests/testdata/mimic_demo-carevue/dyn.parquet differ
diff --git a/tests/testdata/mimic_demo-carevue/features.parquet b/tests/testdata/mimic_demo-carevue/features.parquet
new file mode 100644
index 0000000..98e92d5
Binary files /dev/null and b/tests/testdata/mimic_demo-carevue/features.parquet differ
diff --git a/tests/testdata/mimic_demo-carevue/sta.parquet b/tests/testdata/mimic_demo-carevue/sta.parquet
new file mode 100644
index 0000000..1985177
Binary files /dev/null and b/tests/testdata/mimic_demo-carevue/sta.parquet differ
diff --git a/tests/testdata/mimic_demo/dyn.parquet b/tests/testdata/mimic_demo/dyn.parquet
index a97f594..6755627 100644
Binary files a/tests/testdata/mimic_demo/dyn.parquet and b/tests/testdata/mimic_demo/dyn.parquet differ
diff --git a/tests/testdata/mimic_demo/sta.parquet b/tests/testdata/mimic_demo/sta.parquet
index 81997e1..f2a97fe 100644
Binary files a/tests/testdata/mimic_demo/sta.parquet and b/tests/testdata/mimic_demo/sta.parquet differ