diff --git a/conversionscript.py b/conversionscript.py
index c2b0fc4..e572cf6 100755
--- a/conversionscript.py
+++ b/conversionscript.py
@@ -1,8 +1,7 @@
 #!/usr/bin/env python3
 # -*- coding: utf-8 -*-
 
-from OMPython import OMCSessionZMQ
-import pyparsing
+from OMPython import OMCSessionZMQ, pyparsing
 import argparse
 import glob
 import json
@@ -13,6 +12,7 @@
 from multiprocessing import Pool
 import time
 
+
 parser = argparse.ArgumentParser(description='OpenModelica library testing tool')
 parser.add_argument('libdir', nargs=1)
 parser.add_argument('--diff', action="store_true")
@@ -32,6 +32,17 @@
 os.mkdir("converted-libraries/.openmodelica")
 os.mkdir("converted-libraries/.openmodelica/libraries")
 
+def omcAssert(omc, cmd, extra=""):
+  res = omc.sendExpression(cmd)
+  if not res:
+    raise Exception(cmd + "\n" + extra + "\n" + (omc.sendExpression("getErrorString()") or ""))
+
+def omcSendExpression(omc, cmd, extra=""):
+  try:
+    return omc.sendExpression(cmd)
+  except pyparsing.ParseException as e:
+    raise Exception(str(e) + "\n" + cmd + "\n" + extra + "\n" + (omc.sendExpression("getErrorString()") or ""))
+
 mslPath = "%s/Modelica 4.0.0+maint.om/" % libdir
 with open("%s/openmodelica.metadata.json" % mslPath) as f:
   mslData = json.load(f)
@@ -72,7 +83,7 @@ def convertPackage(p):
   print("Start working on %s" % libnameOnFile)
   omc = OMCSessionZMQ()
   libnameOnFileFullPath = "converted-libraries/.openmodelica/libraries/%s/package.mo" % libnameOnFile
-  omc.sendExpression('loadFile("%s", uses=false)' % libnameOnFileFullPath)
+  omcAssert(omc, 'loadFile("%s", uses=false)' % libnameOnFileFullPath)
   errString = omc.sendExpression("getErrorString()")
   if errString:
     print(errString)
@@ -81,12 +92,12 @@ def convertPackage(p):
     raise Exception("Expected to have loaded %s but got %s" % (libnameOnFileFullPath, loadedFilePath))
   gcProfStatsBeforeConversion = omc.sendExpression("GC_get_prof_stats()")
   timeBeforeConvert = time.time()
-  omc.sendExpression('runConversionScript(%s, "%s")' % (libname, conversionScript))
+  omcAssert(omc, 'runConversionScript(%s, "%s")' % (libname, conversionScript))
   print("runConversionScript(%s, %s) OK" % (libnameOnFile, conversionScript))
   uses = data["uses"]
   for (n,v) in data["uses"].items():
     if n in ["Modelica", "ModelicaServices", "Complex"]:
-      omc.sendExpression('addClassAnnotation(%s, annotate=$annotation(uses(%s(version="4.0.0"))))' % (libname, n))
+      omcAssert(omc, 'addClassAnnotation(%s, annotate=$annotation(uses(%s(version="4.0.0"))))' % (libname, n))
       data["uses"][n] = "4.0.0"
   names = omc.sendExpression('getClassNames(%s, sort=true, recursive=true)' % libname)
   names = list(names)
@@ -138,7 +149,7 @@ def convertPackage(p):
           print(errStr)
         raise Exception('--allowErrorsInDiff is not active:\necho(false);before:=readFile("%s");\nafter:=readFile("%s");echo(true);\ndiffModelicaFileListings(before, after, OpenModelica.Scripting.DiffFormat.plain, failOnSemanticsChange=true);\ngetErrorString();' % (oldFile, newFile))
     else:
-      omc.sendExpression('writeFile("%s", res)' % (newFile))
+      omcAssert(omc, 'writeFile("%s", res)' % (newFile))
     isDiff = before != res
     if before != res:
       nDiff += 1
diff --git a/requirements.txt b/requirements.txt
index 306e8e7..7c5e0e0 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -4,6 +4,6 @@ juliacall
 matplotlib
 monotonic
 natsort
-OMPython==4.0
+ompython==3.6
 psutil
 simplejson
diff --git a/shared.py b/shared.py
index f0eeeab..2f9b7a3 100644
--- a/shared.py
+++ b/shared.py
@@ -74,9 +74,6 @@ def getReferenceFileName(conf):
       else:
         modelName += "."+conf["referenceFileNameExtraName"]
     referenceFile = conf["referenceFiles"]+"/"+modelName.replace(".",conf["referenceFileNameDelimiter"])+(conf.get("referenceFinalDot") or ".")+conf["referenceFileExtension"]
-    if os.path.exists(referenceFile):
-      referenceFile = os.path.abspath(referenceFile)
-
     if not os.path.exists(referenceFile) and not os.path.isdir(referenceFile):
       if conf.get("allReferenceFilesExist"):
         raise Exception("Missing reference file %s for config %s" % (referenceFile,conf))
@@ -108,3 +105,5 @@ def isFMPy(fmisimulator):
     return 'fmpy' in fmisimulator
   else:
     return False
+
+
diff --git a/single-model.py b/single-model.py
index c3cd0aa..d72e769 100755
--- a/single-model.py
+++ b/single-model.py
@@ -1,7 +1,8 @@
 #!/usr/bin/env python3
 # -*- coding: utf-8 -*-
 
-import argparse
+import sys, argparse
+import simplejson as json
 import shared
 
 parser = argparse.ArgumentParser(description='OpenModelica model testing report generation tool')
@@ -20,7 +21,8 @@
 
 libs = {}
 
-import sqlite3, datetime
+import cgi, sqlite3, time, datetime
+from omcommon import friendlyStr, multiple_replace
 
 conn = sqlite3.connect('sqlite3.db')
 cursor = conn.cursor()
diff --git a/test.py b/test.py
index 66c235a..5ee14df 100755
--- a/test.py
+++ b/test.py
@@ -8,10 +8,11 @@
 if (sys.version_info < (3, 0)):
   raise Exception("Python2 is no longer supported")
 
-import html, shutil, os, re, glob, time, argparse, sqlite3, datetime, math
+import html, shutil, os, re, glob, time, argparse, sqlite3, datetime, math, platform
 from joblib import Parallel, delayed
 import simplejson as json
 import psutil, subprocess, threading, hashlib
+from subprocess import call
 from monotonic import monotonic
 from omcommon import friendlyStr, multiple_replace
 from natsort import natsorted
@@ -259,19 +260,14 @@ def target():
   print("Error: Expected at least one configuration file to start the library test")
   sys.exit(1)
 
-from OMPython import OMCSessionZMQ, OMCProcessDocker, OMCSessionException
+from OMPython import OMCSession, OMCSessionZMQ
 
 # Try to make the processes a bit nicer...
 os.environ["GC_MARKERS"]="1"
 
 print("Start OMC version")
 
-if docker:
-  omc = OMCProcessDocker(docker=docker, dockerExtraArgs=dockerExtraArgs)
-  omhome=omc.sendExpression('getInstallationDirectoryPath()')
-  omc_version=omc.sendExpression('getVersion()')
-  ompython_omc_version=omc_version
-elif ompython_omhome != "":
+if ompython_omhome != "":
   # Use a different OMC for running OMPython than for running the tests
   omhome = os.environ["OPENMODELICAHOME"]
   omc_version = check_output_log(omc_cmd + ["--version"], stderr=subprocess.STDOUT).decode("ascii").strip()
@@ -280,11 +276,10 @@ def target():
   ompython_omc_version=omc.sendExpression('getVersion()')
   os.environ["OPENMODELICAHOME"] = omhome
 else:
-  omc = OMCSessionZMQ()
+  omc = OMCSessionZMQ(docker=docker, dockerExtraArgs=dockerExtraArgs)
   omhome=omc.sendExpression('getInstallationDirectoryPath()')
   omc_version=omc.sendExpression('getVersion()')
   ompython_omc_version=omc_version
-
 ompython_omc_version=ompython_omc_version.replace("OMCompiler","").strip()
 
 def timeSeconds(f):
@@ -663,12 +658,11 @@ def hashReferenceFiles(s):
         raise Exception("Library %s has both libraryVersionLatestInPackageManager:true and libraryVersionExactMatch:true! Make up your mind." % libName)
       exactMatch=', requireExactVersion=true'
 
-    try:
-      omc.sendExpression('loadModel(%s,%s%s)' % (lib,versions,exactMatch))
-    except OMCSessionException as e:
-        print("Failed to load library %s %s" % (library,versions))
-        print(e)
-
+    if not omc.sendExpression('loadModel(%s,%s%s)' % (lib,versions,exactMatch)):
+      try:
+        print("Failed to load library %s %s: %s" % (library,versions,omc.sendExpression('OpenModelica.Scripting.getErrorString()')))
+      except:
+        print("Failed to load library %s %s. OpenModelica.Scripting.getErrorString() failed..." % (library,conf["libraryVersion"]))
   # adrpo: do not sort the top level names as sometimes that loads a bad MSL version
   # conf["loadFiles"] = sorted(omc.sendExpression("{getSourceFile(cl) for cl in getClassNames()}"))
   conf["loadFiles"] = omc.sendExpression("{getSourceFile(cl) for cl in getClassNames()}")
@@ -727,13 +721,7 @@ def hashReferenceFiles(s):
   if conf.get("fmi") and fmisimulatorversion:
     conf["libraryVersionRevision"] = conf["libraryVersionRevision"] + " " + fmisimulatorversion.decode("ascii")
     conf["libraryLastChange"] = conf["libraryLastChange"] + " " + fmisimulatorversion.decode("ascii")
-  res = []
-  try:
-    res = omc.sendExpression('{c for c guard isExperiment(c) and not regexBool(typeNameString(x), "^Modelica_Synchronous\\\\.WorkInProgress") in getClassNames(%s, recursive=true)}' % library)
-  except OMCSessionException as e:
-    print("Failed to get class names of library %s", library)
-    print(e)
-
+  res=omc.sendExpression('{c for c guard isExperiment(c) and not regexBool(typeNameString(x), "^Modelica_Synchronous\\.WorkInProgress") in getClassNames(%s, recursive=true)}' % library)
   if conf.get("ignoreModelPrefix"):
     if isinstance(conf["ignoreModelPrefix"], list):
       prefixes = conf["ignoreModelPrefix"]
diff --git a/testmodel.py b/testmodel.py
index e7a0a0b..4d16ba8 100755
--- a/testmodel.py
+++ b/testmodel.py
@@ -2,9 +2,10 @@
 # -*- coding: utf-8 -*-
 
 import argparse, os, sys, signal, threading, psutil, subprocess, shutil
+from asyncio.subprocess import STDOUT
 import simplejson as json
 from monotonic import monotonic
-from OMPython import OMCSessionZMQ, OMCProcessDocker
+from OMPython import FindBestOMCSession, OMCSession, OMCSessionZMQ
 import shared, glob
 
 parser = argparse.ArgumentParser(description='OpenModelica library testing tool helper (single model)')
@@ -57,7 +58,7 @@ def writeResult():
 
 startJob=monotonic()
 
-def quit_omc(omc: OMCSessionZMQ | None):
+def quit_omc(omc):
   if omc is None:
     return omc
   try:
@@ -71,7 +72,7 @@ def quit_omc(omc: OMCSessionZMQ | None):
   omc = None
   return omc
 
-def writeResultAndExit(exitStatus: int, useOsExit: bool = False, omc: OMCSessionZMQ | None = None, omc_new: OMCSessionZMQ | None = None):
+def writeResultAndExit(exitStatus, useOsExit=False, omc=None, omc_new=None):
   writeResult()
   print("Calling exit ...")
   with open(errFile, 'a+') as fp:
@@ -89,7 +90,7 @@ def writeResultAndExit(exitStatus: int, useOsExit: bool = False, omc: OMCSession
   else:
     sys.exit(exitStatus)
 
-def sendExpressionTimeout(omc: OMCSessionZMQ, cmd: str, timeout: int):
+def sendExpressionTimeout(omc, cmd, timeout):
   with open(errFile, 'a+') as fp:
     fp.write("%s [Timeout %s]\n" % (cmd, timeout))
   def target(res):
@@ -250,11 +251,7 @@ def target(res):
 os.environ["OPENMODELICAHOME"] = omhome
 
 def createOmcSession():
-  if docker:
-    return OMCProcessDocker(docker=docker, dockerExtraArgs=dockerExtraArgs, timeout=5)
-  else:
-    return OMCSessionZMQ(timeout=5)
-
+  return OMCSession(docker=docker, dockerExtraArgs=dockerExtraArgs, timeout=5) if corbaStyle else OMCSessionZMQ(docker=docker, dockerExtraArgs=dockerExtraArgs, timeout=5)
 def createOmcSessionNew():
   if ompython_omhome != "":
     os.environ["OPENMODELICAHOME"] = ompython_omhome