diff --git a/CHANGELOG.md b/CHANGELOG.md
index b245e3081d38..c69effd0fff5 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -17,6 +17,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Deprecated
 
+## [2.39.7] - 2023-07-18
+
+### Fixed
+
+- Fix a bug so that MultigroupServer does not allow a file written by multiple processes at the same time.
+
 ## [2.39.6] - 2023-07-18
 
 ### Changed
@@ -30,6 +36,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## [2.39.5] - 2023-07-10
 
 ### Fixed
+
 - Fixed logic in generating the names of the split fields. If the alias field in the History.rc has separators (;), each substring is used to name the resulting fields. If there are no separators, this will be the exact name of the first split field
 
 ## [2.39.4] - 2023-06-23
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 68c38c821d3c..566a48858a98 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -8,7 +8,7 @@ endif ()
 
 project (
   MAPL
-  VERSION 2.39.6
+  VERSION 2.39.7
   LANGUAGES Fortran CXX C)  # Note - CXX is required for ESMF
 
 # Set the possible values of build type for cmake-gui
diff --git a/pfio/CMakeLists.txt b/pfio/CMakeLists.txt
index c56e3722d7ec..9bb4fbac29fa 100644
--- a/pfio/CMakeLists.txt
+++ b/pfio/CMakeLists.txt
@@ -117,7 +117,7 @@ if (BUILD_WITH_PFLOGGER)
 endif ()
 
 esma_add_library (${this} SRCS ${srcs} DEPENDENCIES MAPL.shared MAPL.profiler NetCDF::NetCDF_Fortran NetCDF::NetCDF_C TYPE ${MAPL_LIBRARY_TYPE})
-target_link_libraries (${this} PUBLIC GFTL_SHARED::gftl-shared PFLOGGER::pflogger PRIVATE MPI::MPI_Fortran)
+target_link_libraries (${this} PUBLIC GFTL::gftl-v2 GFTL_SHARED::gftl-shared-v2 PFLOGGER::pflogger PRIVATE MPI::MPI_Fortran)
 # CMake has an OpenMP issue with NAG Fortran: https://gitlab.kitware.com/cmake/cmake/-/issues/21280
 if (NOT CMAKE_Fortran_COMPILER_ID MATCHES "NAG")
    target_link_libraries(${this} PRIVATE OpenMP::OpenMP_Fortran)
diff --git a/pfio/MultiGroupServer.F90 b/pfio/MultiGroupServer.F90
index 32798edbe21c..bc2220dccaf0 100644
--- a/pfio/MultiGroupServer.F90
+++ b/pfio/MultiGroupServer.F90
@@ -46,6 +46,7 @@ module pFIO_MultiGroupServerMod
    use pFIO_AbstractRequestHandleMod
    use pFIO_FileMetadataMod
    use pFIO_IntegerMessageMapMod
+   use gFTL2_StringSet, StringSetIterator =>SetIterator
    use mpi
    use pFlogger, only: logging, Logger
 
@@ -87,6 +88,8 @@ module pFIO_MultiGroupServerMod
       module procedure new_MultiGroupServer
    end interface MultiGroupServer
 
+   integer, parameter :: FNAME_LEN = 512
+
 contains
 
    function new_MultiGroupServer(server_comm, port_name, nwriter_per_node, with_profiler, rc) result(s)
@@ -335,6 +338,7 @@ subroutine receive_output_data(this, rc)
      type (HistoryCollection), pointer :: hist_collection
      integer, pointer :: i_ptr(:)
      class (AbstractRequestHandle), pointer :: handle
+     character(len=FNAME_LEN) :: FileName
 
      if (associated(ioserver_profiler)) call ioserver_profiler%start("receive_data")
      client_num = this%threads%size()
@@ -395,6 +399,15 @@ subroutine receive_output_data(this, rc)
         if (this%I_am_front_root) then
            collection_id = collection_ids%at(collection_counter)
            call Mpi_Send(collection_id, 1, MPI_INTEGER, this%back_ranks(1), this%back_ranks(1), this%server_comm, ierror)
+           msg =>f_d_ms(collection_counter)%msg_vec%at(1) ! just pick first one. All messages should have the same filename
+           select type (q=>msg)
+           class is (AbstractCollectiveDataMessage)
+              Filename = q%file_name
+              call Mpi_Send(FileName, FNAME_LEN, MPI_CHARACTER, this%back_ranks(1), this%back_ranks(1), this%server_comm, ierror)
+           class default
+              _FAIL( "yet to implemented")
+           end select
+
            ! here thread_ptr can point to any thread
            hist_collection => thread_ptr%hist_collections%at(collection_id)
            call hist_collection%fmd%serialize(buffer)
@@ -438,6 +451,7 @@ subroutine start_back(this, rc)
      integer, parameter :: stag = 6782
 
      integer :: status
+     type (StringSet) :: FilesBeingWritten
 
      allocate(this%serverthread_done_msgs(1))
      this%serverthread_done_msgs(:) = .false.
@@ -462,6 +476,7 @@ subroutine start_back_captain(rc)
        integer :: i, no_job, local_rank, node_rank, nth_writer
        integer :: terminate, idle_writer, ierr
        integer :: MPI_STAT(MPI_STATUS_SIZE)
+       character(len=FNAME_LEN)         :: FileName
 
        nwriter_per_node = this%nwriter/this%Node_Num
        allocate(num_idlePEs(0:this%Node_Num-1))
@@ -482,8 +497,12 @@ subroutine start_back_captain(rc)
               this%front_ranks(1), this%back_ranks(1), this%server_comm, &
               MPI_STAT, ierr)
          if (collection_id == -1) exit
+
+         call MPI_recv( FileName, FNAME_LEN , MPI_CHARACTER, &
+              this%front_ranks(1), this%back_ranks(1), this%server_comm, &
+              MPI_STAT, ierr)
          ! 2) get an idle processor and notify front root
-         call dispatch_work(collection_id, idleRank, num_idlePEs, rc=status)
+         call dispatch_work(collection_id, idleRank, num_idlePEs, FileName, rc=status)
          _VERIFY(status)
        enddo ! while .true.
 
@@ -498,16 +517,19 @@ subroutine start_back_captain(rc)
        _RETURN(_SUCCESS)
      end subroutine start_back_captain
 
-     subroutine dispatch_work(collection_id, idleRank, num_idlePEs, rc)
+     subroutine dispatch_work(collection_id, idleRank, num_idlePEs, FileName, rc)
        integer, intent(in) :: collection_id
        integer, intent(inout) :: idleRank(0:,0:)
        integer, intent(inout) :: num_idlePEs(0:)
+       character(*), intent(in) :: FileName
        integer, optional, intent(out) :: rc
 
        integer :: MPI_STAT(MPI_STATUS_SIZE)
        integer :: local_rank, idle_writer, nth_writer, node_rank
        integer :: i, ierr, nwriter_per_node
        logical :: flag
+       character(len=FNAME_LEN) :: FileDone
+       type (StringSetIterator) :: iter
 
        ! 2.1)  try to retrieve idle writers
        !       keep looping (waiting) until there are idle processors
@@ -526,10 +548,21 @@ subroutine dispatch_work(collection_id, idleRank, num_idlePEs, rc)
                num_idlePEs(node_rank) = num_idlePEs(node_rank) + 1
                nth_writer = mod(local_rank, nwriter_per_node)
                idleRank(node_rank, nth_writer) = local_rank
+
+               call MPI_recv(FileDone, FNAME_LEN, MPI_CHARACTER, &
+                             local_rank, stag+1, this%back_comm, &
+                             MPI_STAT, ierr)
+
+               iter = FilesBeingWritten%find(FileDone)
+               _ASSERT( iter /= FilesBeingWritten%end(), "FileDone should be in the set")
+               iter = FilesBeingWritten%erase(iter)
              endif
           enddo
           ! if there is no idle processor, get back to probe
           if (all(num_idlePEs == 0)) cycle
+          ! if this file is still being written, get back to probe  
+          iter = FilesBeingWritten%find(FileName)
+          if (iter /= FilesBeingWritten%end()) cycle 
 
           ! get the node with the most idle processors
           node_rank = maxloc(num_idlePEs, dim=1) - 1
@@ -541,7 +574,8 @@ subroutine dispatch_work(collection_id, idleRank, num_idlePEs, rc)
             exit
           enddo
           _ASSERT(1<= idle_writer .and. idle_writer <= this%nwriter-1, "wrong local rank of writer")
-          exit ! exit while loop after get one idle processor
+          call FilesBeingWritten%insert(FileName)
+          exit ! exit the loop after get one idle processor and the file is done
        enddo ! while,  get one idle writer
 
        ! 2.2) tell front comm which idel_worker is ready
@@ -559,6 +593,7 @@ subroutine terminate_back_writers(idleRank, rc)
        integer :: MPI_STAT(MPI_STATUS_SIZE)
        integer :: node_rank, local_rank, nth_writer
        integer :: ierr, no_job, nwriter_per_node, idle_writer
+       character(len=FNAME_LEN) :: FileDone
 
        no_job = -1
        nwriter_per_node = size(idleRank, 2)
@@ -574,6 +609,9 @@ subroutine terminate_back_writers(idleRank, rc)
              call MPI_recv( idle_writer, 1, MPI_INTEGER, &
                             local_rank, stag, this%back_comm, &
                             MPI_STAT, ierr)
+             call MPI_recv( FileDone, FNAME_LEN, MPI_CHARACTER, &
+                            local_rank, stag+1, this%back_comm, &
+                            MPI_STAT, ierr)
              _ASSERT(local_rank == idle_writer, "local_rank and idle_writer should match")
              call MPI_send(no_job, 1, MPI_INTEGER, local_rank, local_rank, this%back_comm, ierr)
           endif
@@ -612,6 +650,7 @@ subroutine start_back_writers(rc)
        type(AdvancedMeter) :: file_timer
        real(kind=REAL64) :: time
        character(len=:), allocatable :: filename
+       character(len=FNAME_LEN) :: FileDone
        real(kind=REAL64) :: file_size, speed
 
        class(Logger), pointer :: lgr
@@ -828,7 +867,10 @@ subroutine start_back_writers(rc)
          !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
          ! telling captain it is idle by sending its own rank
          !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+
          call MPI_send(back_local_rank, 1, MPI_INTEGER, 0, stag, this%back_comm , ierr)
+         FileDone = Filename
+         call MPI_send(FileDone, FNAME_LEN, MPI_CHARACTER, 0, stag+1, this%back_comm , ierr)
        enddo
        _RETURN(_SUCCESS)
      end subroutine start_back_writers