diff --git a/ChangeLog b/ChangeLog
index 6cd3e71f0b444ea91e918a00135bb8c7126c7cae..e6dcc1b445401b3aba6e841f6a7f664a42bd987e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2024-10-19  Uwe Schulzweida
+
+	* added support for non-thread-safe NetCDF4/HDF5 library
+
 2024-10-18  Uwe Schulzweida
 
 	* setpartabn: convert parameter failed (bug fix)
diff --git a/NEWS b/NEWS
index 19f869799acb35c27a7a9116436d3e89662e1d02..6e1c87c605151a45821210d30acba4ad6f2c6922 100644
--- a/NEWS
+++ b/NEWS
@@ -6,10 +6,13 @@ Improvement
 Version 2.5.0 (21 Oct 2024):
 
    New features:
+     * Added support for non-thread-safe NetCDF4/HDF5 library
      * Remapstat: added support for unstructured target grids
      * Timselstat: added support for parameter nskip=-1
    New operators:
    Fixed bugs:
+     * setpartabn: convert parameter failed
+     * ydrunpctl: parameter pm=r8 failed
 
 Version 2.4.4 (18 Sep 2024):
 
diff --git a/src/cdo_settings.cc b/src/cdo_settings.cc
index a0612b8659fa619a2a553f8ec8b922b92e25ccae..98c00d1b9671f5fdacbb2ec37b0115b2876b38ec 100644
--- a/src/cdo_settings.cc
+++ b/src/cdo_settings.cc
@@ -98,7 +98,7 @@ set_cdi_options()
       fprintf(stderr, "\n");
     }
 
-  if (Options::test) cdiDefGlobal("THREADSAFE", 1);
+  if (Threading::cdoLockIO == false) cdiDefGlobal("THREADSAFE", 1);
 
   if (Options::CMOR_Mode) cdiDefGlobal("CMOR_MODE", Options::CMOR_Mode);  // TODO maybe reposition into effect of "cmor"
   if (Options::CDO_Reduce_Dim) cdiDefGlobal("REDUCE_DIM", Options::CDO_Reduce_Dim);
diff --git a/src/fileStream.cc b/src/fileStream.cc
index 849dbc4e494a4d3beef3691d318de21be5eb9859..568efc10ead49871e53023ece9ebde2d9f2458c7 100644
--- a/src/fileStream.cc
+++ b/src/fileStream.cc
@@ -82,7 +82,7 @@ FileStream::open_write(int p_filetype)
       if (rstatus != -1) query_user_exit(m_name);
     }
   if (p_filetype == CDI_UNDEFID) p_filetype = CDI_FILETYPE_GRB;
-
+  /*
 #ifndef HAVE_NC4HDF5_THREADSAFE
   auto outputFileTypeIsNetCDF4 = (p_filetype == CDI_FILETYPE_NC4 || p_filetype == CDI_FILETYPE_NC4C);
   if (inputFileTypeIsNetCDF4 && outputFileTypeIsNetCDF4 && get_process_num() > 1 && Threading::cdoLockIO == false)
@@ -91,7 +91,7 @@ FileStream::open_write(int p_filetype)
       cdo_warning("Use a thread-safe NetCDF4/HDF5 library or the CDO option -L to avoid such errors.");
     }
 #endif
-
+  */
   // TODO FIX THIS: if (FileStream::timersEnabled()) cdo::writeTimer.start();
 
   open_lock();