diff --git a/.gitignore b/.gitignore
index f7e62d9..d2748b4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -169,3 +169,9 @@ cython_debug/
 
 .qodo
 /tests/test_data/RD139_Narrow_UPS1_0_1fmol_inj1.mzML
+
+# DIA-NN config file generated by tests
+diann_config.cfg
+
+# Parquet files generated by tests
+*.parquet
diff --git a/environment.yml b/environment.yml
index 31f1371..157604c 100644
--- a/environment.yml
+++ b/environment.yml
@@ -6,8 +6,8 @@ channels:
   - nodefaults
 dependencies:
   - click
-  - sdrf-pipelines>=0.0.31
-  - pyopenms>=3.3.0
+  - sdrf-pipelines==0.0.33
+  - pyopenms>=3.2.0
   - pandas
   - pyarrow>=16.1.0
   - scipy
\ No newline at end of file
diff --git a/pyproject.toml b/pyproject.toml
index 93ade61..be05058 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -31,8 +31,8 @@ packages = [
 [tool.poetry.dependencies]
 python = "*"
 click = "*"
-sdrf-pipelines = ">=0.0.32"
-pyopenms = ">=3.2.0"
+sdrf-pipelines = "==0.0.33"
+pyopenms = ">=3.3.0"
 pandas = "*"
 pyarrow = ">=16.1.0"
 scipy = "*"
diff --git a/quantmsutils/__init__.py b/quantmsutils/__init__.py
index 40b07ef..5681085 100644
--- a/quantmsutils/__init__.py
+++ b/quantmsutils/__init__.py
@@ -1 +1 @@
-__version__ = "0.0.23"
+__version__ = "0.0.24"
diff --git a/quantmsutils/diann/dianncfg.py b/quantmsutils/diann/dianncfg.py
index 1b6003e..20ba92f 100644
--- a/quantmsutils/diann/dianncfg.py
+++ b/quantmsutils/diann/dianncfg.py
@@ -7,13 +7,38 @@
 import logging
 import re
 from typing import List, Tuple
-
+from collections import defaultdict
 import click
 from sdrf_pipelines.openms.unimod import UnimodDatabase
 
 logging.basicConfig(format="%(asctime)s [%(funcName)s] - %(message)s", level=logging.DEBUG)
 logger = logging.getLogger(__name__)
 
+# Lazy initialization of UnimodDatabase for improved testability.
+# The database is created on first access rather than at module import time,
+# which allows tests to mock or replace it more easily.
+_unimod_database = None
+
+
+def get_unimod_database():
+    """
+    Get the UnimodDatabase instance, creating it lazily on first access.
+
+    This pattern improves testability by avoiding database initialization at module
+    import time. For testing purposes, the internal _unimod_database variable can be
+    set to None to force re-initialization on the next call.
+
+    :return: The UnimodDatabase instance.
+    """
+    global _unimod_database
+    if _unimod_database is None:
+        _unimod_database = UnimodDatabase()
+    return _unimod_database
+
+
+# Met-loss modification constant (UniMod:765) with mass shift and site specification
+MET_LOSS_MODIFICATION = "UniMod:765,-131.040485,*nM"
+
 
 @click.command("dianncfg", short_help="Create DIA-NN config file with enzyme and PTMs")
 @click.option("--enzyme", "-e", help="")
@@ -32,8 +57,7 @@ def dianncfg(ctx, enzyme, fix_mod, var_mod):
     :param var_mod: A string of variable modifications, separated by commas.
     """
     cut = enzyme_cut(enzyme)
-    unimod_database = UnimodDatabase()
-    fix_ptm, var_ptm = convert_mod(unimod_database, fix_mod, var_mod)
+    fix_ptm, var_ptm = convert_mod(fix_mod, var_mod)
 
     var_ptm_str = " --var-mod "
     fix_ptm_str = " --fixed-mod "
@@ -42,83 +66,106 @@ def dianncfg(ctx, enzyme, fix_mod, var_mod):
     for mod in fix_ptm:
         diann_fix_ptm += fix_ptm_str + mod
     for mod in var_ptm:
-        diann_var_ptm += var_ptm_str + mod
+        if mod == MET_LOSS_MODIFICATION:
+            diann_var_ptm += " --met-excision "
+        else:
+            diann_var_ptm += var_ptm_str + mod
 
     with open("diann_config.cfg", "w") as file:
         file.write("--cut " + cut + diann_fix_ptm + diann_var_ptm)
 
 
-def convert_mod(unimod_database, fix_mod: str, var_mod: str) -> Tuple[List, List]:
+def get_mod(mod, mod_type):
+    """
+    Retrieve and format a modification from the Unimod database for DIA-NN compatibility.
+
+    :param mod: The modification string, typically containing the modification name and site.
+    :param mod_type: The type of modification ('fixed_mod' or 'var_mod').
+    :return: A tuple (diann_mod_accession, site), where diann_mod_accession is a formatted string
+             for DIA-NN and site is the modification site.
+    :raises SystemExit: If the modification is not found in the Unimod database, logs an error and exits.
+    """
     pattern = re.compile(r"\((.*?)\)")
+    modification_found = 0
+    diann_mod_accession = None
+    diann_mod_name = None
+    for modification in get_unimod_database().modifications:
+        if modification.get_name() == mod.split(" ")[0]:
+            diann_mod_accession = modification.get_accession().replace("UNIMOD:", "UniMod:") + "," + str(modification._delta_mono_mass)
+            diann_mod_name = modification.get_name()
+            modification_found = 1
+            break
+
+    if modification_found == 0:
+        logging.error(
+            f"Only Unimod modifications are currently supported for the DIA pipeline. Unsupported modification: {mod}"
+        )
+        exit(1)
+
+    # TODO support DIA multiplex
+    if (
+            "TMT" in diann_mod_name
+            or "Label:" in diann_mod_name
+            or "iTRAQ" in diann_mod_name
+            or "mTRAQ" in diann_mod_name
+            or "Dimethyl:" in diann_mod_name
+    ):
+        logging.error(
+            "quantms DIA-NN workflow only supports LFQ now! Unsupported modifications: "
+            + mod
+        )
+        exit(1)
+
+    sites = re.findall(pattern, " ".join(mod.split(" ")[1:]))
+    if not sites:
+        logging.error(
+            f"No site specification found in modification string: {mod}"
+        )
+        exit(1)
+    site = sites[0]
+    if site == "Protein N-term":
+        site = "*n"
+    elif site == "N-term":
+        site = "n"
+    elif len(site.split(" ")) >= 2:
+        pp = " ".join(site.split(" ")[:-1])
+        if pp == "Protein N-term":
+            pp = "*n"
+        elif pp == "N-term":
+            pp = "n"
+        aa = site.split(" ")[-1]
+        site = pp + aa
+        if site == "*nM" and diann_mod_name == "Met-loss" and mod_type == "var_mod":
+            return diann_mod_accession, site
+        else:
+            logging.error("Restricting to certain terminal AAs isn't directly supported. Please see https://github.com/vdemichev/DiaNN/issues/1791")
+            exit(1)
+    return diann_mod_accession, site
+
+
+def convert_mod(fix_mod: str, var_mod: str) -> Tuple[List, List]:
     var_ptm = []
     fix_ptm = []
-
-    if fix_mod != "":
+    if fix_mod:
+        merged = defaultdict(list)
         for mod in fix_mod.split(","):
-            tag = 0
-            diann_mod = None
-            for modification in unimod_database.modifications:
-                if modification.get_name() == mod.split(" ")[0]:
-                    diann_mod = modification.get_name() + "," + str(modification._delta_mono_mass)
-                    tag = 1
-                    break
-            if tag == 0:
-                logging.info(
-                    "Warning: Currently only supported unimod modifications for DIA pipeline. Skipped: "
-                    + mod
-                )
-                continue
-            site = re.findall(pattern, " ".join(mod.split(" ")[1:]))[0]
-            if site == "Protein N-term":
-                site = "*n"
-            elif site == "N-term":
-                site = "n"
-
-            if (
-                "TMT" in diann_mod
-                or "Label" in diann_mod
-                or "iTRAQ" in diann_mod
-                or "mTRAQ" in diann_mod
-            ):
-                fix_ptm.append(diann_mod + "," + site + "," + "label")
-            elif diann_mod is not None:
-                fix_ptm.append(diann_mod + "," + site)
-            else:
-                print(
-                    "Warning: Currently only supported unimod modifications for DIA pipeline. Skipped: "
-                    + mod
-                )
-
-    if var_mod != "":
+            diann_mod, site = get_mod(mod, "fixed_mod")
+            merged[diann_mod].append(site)
+
+        # merge same modification for different sites
+        for name, site_list in merged.items():
+            site_str = "".join(sorted(set(site_list)))
+            fix_ptm.append(f"{name},{site_str}")
+
+    if var_mod:
+        merged = defaultdict(list)
         for mod in var_mod.split(","):
-            tag = 0
-            diann_mod = None
-            for modification in unimod_database.modifications:
-                if modification.get_name() == mod.split(" ")[0]:
-                    diann_mod = modification.get_name() + "," + str(modification._delta_mono_mass)
-                    tag = 1
-                    break
-            if tag == 0:
-                print(
-                    "Warning: Currently only supported unimod modifications for DIA pipeline. Skipped: "
-                    + mod
-                )
-                continue
-            site = re.findall(pattern, " ".join(mod.split(" ")[1:]))[0]
-            if site == "Protein N-term":
-                site = "*n"
-            elif site == "N-term":
-                site = "n"
-
-            if (
-                "TMT" in diann_mod
-                or "Label" in diann_mod
-                or "iTRAQ" in diann_mod
-                or "mTRAQ" in diann_mod
-            ):
-                var_ptm.append(diann_mod + "," + site + "," + "label")
-            else:
-                var_ptm.append(diann_mod + "," + site)
+            diann_mod, site = get_mod(mod, "var_mod")
+            merged[diann_mod].append(site)
+        # merge same modification for different sites
+        for name, site_list in merged.items():
+            site_str = "".join(sorted(set(site_list)))
+            var_ptm.append(f"{name},{site_str}")
 
     return fix_ptm, var_ptm
 
diff --git a/requirements.txt b/requirements.txt
index 1a53263..b95ff25 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,6 +1,6 @@
 click
-sdrf-pipelines>=0.0.31
-pyopenms>=3.2.0
+sdrf-pipelines==0.0.33
+pyopenms>=3.3.0
 pandas
 pyarrow>=16.1.0
 scipy
diff --git a/tests/test_commands.py b/tests/test_commands.py
index 70885fe..c80380f 100644
--- a/tests/test_commands.py
+++ b/tests/test_commands.py
@@ -84,7 +84,20 @@ def test_diann2mztab_example(self):
         ]
         result = run_cli_command("diann2mztab", args)
         assert result.exit_code == 0
-        # Additional assertions could check for expected output files
+
+    def test_dianncfg_example(self):
+        """Test generating the DIA-NN config with example data"""
+        args = [
+            "--enzyme",
+            "Trypsin",
+            "--fix_mod",
+            "Carbamidomethyl (C)",
+            "--var_mod",
+            "Oxidation (M),Phospho (S),Phospho (T),Phospho (Y),Acetyl (Protein N-term),Acetyl (K),Acetyl (R),Met-loss (Protein N-term M)",
+        ]
+        result = run_cli_command("dianncfg", args)
+
+        assert result.exit_code == 0
 
 
 class TestSamplesheetCommands: