diff --git a/.github/workflows/developer.yml b/.github/workflows/developer.yml
index 9cf92586..2df9d26c 100644
--- a/.github/workflows/developer.yml
+++ b/.github/workflows/developer.yml
@@ -146,7 +146,7 @@ jobs:
 
     - name: upload-test-coverage
       if: matrix.config == 'asan/code coverage'
-      uses: actions/upload-artifact@v3
+      uses: actions/upload-artifact@v4
       with:
         name: g2-test-coverage
         path: |
diff --git a/src/g2_gbytesc.F90 b/src/g2_gbytesc.F90
index 4c76cf29..de841bd0 100644
--- a/src/g2_gbytesc.F90
+++ b/src/g2_gbytesc.F90
@@ -11,7 +11,7 @@
 !> has more elements, use g2_sbytesc().
 !>
 !> @param[in] in Array input.
-!> @param[out] iout Unpacked array output.
+!> @param[inout] iout Unpacked array output.
 !> @param[in] iskip Initial number of bits to skip.
 !> @param[in] nbits Number of bits of each integer in IN to take.
 !>
@@ -32,7 +32,7 @@ end subroutine g2_gbytec
 !> This should be used when input array IN has only one element. If IN
 !> has more elements, use G2_SBYTESC().
 !>
-!> @param[out] out packed array output
+!> @param[inout] out packed array output
 !> @param[in] in unpacked array input
 !> @param[in] iskip initial number of bits to skip
 !> @param[in] nbits Number of bits of each integer in OUT to fill.
diff --git a/src/g2index.F90 b/src/g2index.F90
index 07cbeeb7..5ae1bcd7 100644
--- a/src/g2index.F90
+++ b/src/g2index.F90
@@ -212,6 +212,7 @@ SUBROUTINE GETG2I(LUGI, CBUF, NLEN, NNUM, IRET)
   INTEGER, INTENT(OUT) :: NLEN, NNUM, IRET
   CHARACTER CHEAD*162
   integer :: ios, istat, lbuf, lhead, nskp
+  integer :: index_version
 
   NULLIFY(CBUF)
   NLEN = 0
@@ -219,7 +220,7 @@ SUBROUTINE GETG2I(LUGI, CBUF, NLEN, NNUM, IRET)
   IRET = 4
   CALL BAREAD(LUGI, 0, 162, LHEAD, CHEAD)
   IF (LHEAD .EQ. 162 .AND. CHEAD(42:47) .EQ. 'GB2IX1') THEN
-     READ(CHEAD(82:162), '(8X, 3I10, 2X, A40)', IOSTAT = IOS) NSKP, NLEN, NNUM
+     READ(CHEAD(82:162), '(2X, I1, 5X, 3I10, 2X, A40)', IOSTAT = IOS) index_version, NSKP, NLEN, NNUM
      IF (IOS .EQ. 0) THEN
         ALLOCATE(CBUF(NLEN), STAT = ISTAT)    ! ALLOCATE SPACE FOR CBUF
         IF (ISTAT .NE. 0) THEN
@@ -239,8 +240,8 @@ END SUBROUTINE GETG2I
 !> and byte offsets within the message to each section. The index file
 !> record format is documented in subroutine ixgb2().
 !>
-!> @note Subprogram can be called from a multiprocessing environment.
-!> Do not engage the same logical unit from more than one processor.
+!> This is the legacy function, which always creates version 1 index
+!> files. To create index files of version 1 or 2, use getg2i2r().
 !>
 !> @param[in] lugb Unit of the unblocked GRIB file. Must
 !> be opened by [baopen() or baopenr()]
@@ -265,45 +266,108 @@ END SUBROUTINE GETG2I
 !> - 3 Error deallocating memory.
 !>
 !> @author Mark Iredell @date 1995-10-31
-SUBROUTINE GETG2IR(LUGB, MSK1, MSK2, MNUM, CBUF, NLEN, NNUM, NMESS, IRET)
-  USE RE_ALLOC              ! NEEDED FOR SUBROUTINE REALLOC
+subroutine getg2ir(lugb, msk1, msk2, mnum, cbuf, nlen, nnum, nmess, iret)
+  use re_alloc              ! needed for subroutine realloc
   implicit none
+  character(len = 1), pointer, dimension(:) :: cbuf
+  integer, intent(in) :: lugb, msk1, msk2, mnum
+  integer, intent(out) :: nlen, nnum, nmess, iret
+  
+  interface      ! required for cbuf pointer
+     subroutine getg2i2r(lugb, msk1, msk2, mnum, idxver, cbuf, nlen, &
+          nnum, nmess, iret)
+       character(len = 1), pointer, dimension(:) :: cbuf
+       integer, intent(in) :: lugb, msk1, msk2, mnum, idxver
+       integer, intent(out) :: nlen, nnum, nmess, iret
+     end subroutine getg2i2r
+  end interface
 
-  CHARACTER(LEN = 1), POINTER, DIMENSION(:) :: CBUF
-  INTEGER, INTENT(IN) :: LUGB, MSK1, MSK2, MNUM
-  INTEGER, INTENT(OUT) :: NLEN, NNUM, NMESS, IRET
-  CHARACTER(LEN = 1), POINTER, DIMENSION(:) :: CBUFTMP
+  call getg2i2r(lugb, msk1, msk2, mnum, 1, cbuf, nlen, nnum, nmess, iret)
+end subroutine getg2ir
+
+!> Generate an index record for a message in a GRIB2 file.
+!>
+!> The index record contains byte offsets to the message, it's length,
+!> and byte offsets within the message to each section. The index file
+!> record format is documented in subroutine ixgb2().
+!>
+!> This subroutine is like getg2ir(), but this subroutine can generate
+!> index files in version 1 or 2 format. Use index version 2 for files
+!> > 2 GB.
+!>
+!> @note Subprogram can be called from a multiprocessing environment.
+!> Do not engage the same logical unit from more than one processor.
+!>
+!> @param[in] lugb Unit of the unblocked GRIB file. Must
+!> be opened by [baopen() or baopenr()]
+!> (https://noaa-emc.github.io/NCEPLIBS-bacio/).
+!> @param[in] msk18 Number of bytes to search for first message.
+!> @param[in] msk28 Number of bytes to search for other messages.
+!> @param[in] mnum Number of GRIB messages to skip (usually 0).
+!> @param[in] idxver Index version, 1 for legacy, 2 for files > 2 GB.
+!> @param[out] cbuf Pointer to a buffer that will get the index
+!> records. If any memory is associated with cbuf when this subroutine
+!> is called, cbuf will be nullified in the subroutine. Initially cbuf
+!> will get an allocation of 5000 bytes. realloc() will be used to
+!> increase the size if necessary. Users must free memory that cbuf
+!> points to when cbuf is no longer needed.
+!> @param[out] nlen Total length of index record buffer in bytes.
+!> @param[out] nnum Number of index records, zero if no GRIB
+!> messages are found.
+!> @param[out] nmess Last GRIB message in file successfully processed
+!> @param[out] iret Return code.
+!> - 0 No error.
+!> - 1 Not enough memory available to hold full index buffer.
+!> - 2 Not enough memory to allocate initial index buffer.
+!> - 3 Error deallocating memory.
+!>
+!> @author Mark Iredell, Edward Hartnett @date Feb 4, 2024
+subroutine getg2i2r(lugb, msk18, msk28, mnum, idxver, cbuf, nlen, &
+     nnum, nmess, iret)
+  use re_alloc              ! needed for subroutine realloc
+  implicit none
+
+  character(len = 1), pointer, dimension(:) :: cbuf
+  integer, intent(in) :: lugb
+  integer (kind = 8), intent(in) :: msk18, msk28
+  integer :: msk1, msk2
+  integer, intent(in) :: mnum, idxver
+  integer, intent(out) :: nlen, nnum, nmess, iret
+  character(len = 1), pointer, dimension(:) :: cbuftmp
   integer :: nbytes, newsize, next, numfld, m, mbuf, lskip, lgrib
   integer :: istat, iseek, init, iret1
-  PARAMETER(INIT = 50000, NEXT = 10000)
+  parameter(init = 50000, next = 10000)
 
-  INTERFACE      ! REQUIRED FOR CBUF POINTER
-     SUBROUTINE IXGB2(LUGB, LSKIP, LGRIB, CBUF, NUMFLD, MLEN, IRET)
-       INTEGER, INTENT(IN) :: LUGB, LSKIP, LGRIB
-       CHARACTER(LEN = 1), POINTER, DIMENSION(:) :: CBUF
-       INTEGER, INTENT(OUT) :: NUMFLD, MLEN, IRET
-     END SUBROUTINE IXGB2
-  END INTERFACE
+  interface      ! required for cbuf pointer
+     subroutine ixgb2(lugb, lskip, lgrib, cbuf, numfld, mlen, iret)
+       integer :: lugb, lskip, lgrib
+       character(len = 1), pointer, dimension(:) :: cbuf
+       integer :: numfld, mlen, iret
+     end subroutine ixgb2
+  end interface
+
+  msk1 = msk18
+  msk2 = msk28
 
   ! Initialize.
-  IRET = 0
-  NULLIFY(CBUF)
-  MBUF = INIT
-  ALLOCATE(CBUF(MBUF), STAT = ISTAT)    ! Allocate initial space for cbuf.
-  IF (ISTAT .NE. 0) THEN
-     IRET = 2
-     RETURN
-  ENDIF
+  iret = 0
+  nullify(cbuf)
+  mbuf = init
+  allocate(cbuf(mbuf), stat = istat)    ! allocate initial space for cbuf.
+  if (istat .ne. 0) then
+     iret = 2
+     return
+  endif
 
   ! Search for first grib message.
-  ISEEK = 0
-  CALL SKGB(LUGB, ISEEK, MSK1, LSKIP, LGRIB)
-  DO M = 1, MNUM
-     IF(LGRIB.GT.0) THEN
-        ISEEK = LSKIP + LGRIB
-        CALL SKGB(LUGB, ISEEK, MSK2, LSKIP, LGRIB)
-     ENDIF
-  ENDDO
+  iseek = 0
+  call skgb(lugb, iseek, msk1, lskip, lgrib)
+  do m = 1, mnum
+     if(lgrib.gt.0) then
+        iseek = lskip + lgrib
+        call skgb(lugb, iseek, msk2, lskip, lgrib)
+     endif
+  enddo
 
   ! Get index records for every grib message found.
   NLEN = 0
@@ -342,7 +406,7 @@ END SUBROUTINE IXGB2
      ISEEK = LSKIP + LGRIB
      CALL SKGB(LUGB, ISEEK, MSK2, LSKIP, LGRIB)
   ENDDO
-END SUBROUTINE GETG2IR
+END SUBROUTINE GETG2I2R
 
 !> Find information about a GRIB field from the index and fill a @ref
 !> grib_mod::gribfield.
@@ -646,21 +710,93 @@ END SUBROUTINE GETGB2S
 !> - byte kk + 1-  ll the data representation section (drs)
 !> - byte ll + 1-ll + 6 first 6 bytes of the bit map section (bms)
 !>
-!> @param[in] lugb Unit of the unblocked GRIB file. Must
+!> @param lugb Unit of the unblocked GRIB file. Must
 !> be opened by [baopen() or baopenr()]
 !> (https://noaa-emc.github.io/NCEPLIBS-bacio/).
-!> @param[in] lskip Number of bytes to skip before GRIB message.
-!> @param[in] lgrib Number of bytes in GRIB message. When subroutine is
+!> @param lskip Number of bytes to skip before GRIB message.
+!> @param lgrib Number of bytes in GRIB message. When subroutine is
 !> called, this must be set to the size of the cbuf buffer.
-!> @param[out] cbuf Pointer to a buffer that will get the index
+!> @param cbuf Pointer to a buffer that will get the index
+!> records. If any memory is associated with cbuf when this subroutine
+!> is called, cbuf will be nullified in the subroutine. Initially cbuf
+!> will get an allocation of 5000 bytes. realloc() will be used to
+!> increase the size if necessary. Users must free memory that cbuf
+!> points to when cbuf is no longer needed.
+!> @param numfld Number of index records created.
+!> @param mlen Total length of all index records.
+!> @param iret Return code
+!> - 0 No error
+!> - 1 Not enough memory available to hold full index buffer.
+!> - 2 I/O error in read.
+!> - 3 GRIB message is not edition 2.
+!> - 4 Not enough memory to allocate extent to index buffer.
+!> - 5 Unidentified GRIB section encountered.
+!>
+!> @author Mark Iredell @date 1995-10-31
+subroutine ixgb2(lugb, lskip, lgrib, cbuf, numfld, mlen, iret)
+  implicit none
+  integer :: lugb, lskip, lgrib
+  character(len = 1), pointer, dimension(:) :: cbuf
+  integer :: numfld, mlen, iret
+  integer (kind = 8) :: lskip8
+
+  interface
+     subroutine ix2gb2(lugb, lskip8, idxver, lgrib, cbuf, numfld, mlen, iret)
+       integer :: lugb
+       integer (kind = 8) :: lskip8
+       integer :: idxver, lgrib
+       character(len = 1), pointer, dimension(:) :: cbuf
+       integer :: numfld, mlen, iret
+     end subroutine ix2gb2
+  end interface
+
+  lskip8 = lskip
+  call ix2gb2(lugb, lskip8, 1, lgrib, cbuf, numfld, mlen, iret)
+end SUBROUTINE IXGB2
+
+!> Generate an index record for each field in a GRIB2 message. The index
+!> records are written to index buffer pointed to by cbuf. All integers
+!> in the index are in big-endian format.
+!>
+!> This subroutine is called by getg2ir(), which packages the index
+!> records into an index file.
+!>
+!> The index buffer returned contains index records with the
+!> format:
+!> - byte 001 - 004 length of index record
+!> - byte 005 - 008 bytes to skip in data file before GRIB message
+!> - byte 009 - 012 bytes to skip in message before lus (local use) set = 0, if no local section.
+!> - byte 013 - 016 bytes to skip in message before gds
+!> - byte 017 - 020 bytes to skip in message before pds
+!> - byte 021 - 024 bytes to skip in message before drs
+!> - byte 025 - 028 bytes to skip in message before bms
+!> - byte 029 - 032 bytes to skip in message before data section
+!> - byte 033 - 040 bytes total in the message
+!> - byte 041 - 041 GRIB version number (2)
+!> - byte 042 - 042 message discipline
+!> - byte 043 - 044 field number within GRIB2 message
+!> - byte 045 -  ii identification section (ids)
+!> - byte ii + 1-  jj grid definition section (gds)
+!> - byte jj + 1-  kk product definition section (pds)
+!> - byte kk + 1-  ll the data representation section (drs)
+!> - byte ll + 1-ll + 6 first 6 bytes of the bit map section (bms)
+!>
+!> @param lugb Unit of the unblocked GRIB file. Must
+!> be opened by [baopen() or baopenr()]
+!> (https://noaa-emc.github.io/NCEPLIBS-bacio/).
+!> @param lskip8 Number of bytes to skip before GRIB message.
+!> @param idxver Index version, 1 for legacy, 2 for GRIB2 files > 2 GB.
+!> @param lgrib Number of bytes in GRIB message. When subroutine is
+!> called, this must be set to the size of the cbuf buffer.
+!> @param cbuf Pointer to a buffer that will get the index
 !> records. If any memory is associated with cbuf when this subroutine
 !> is called, cbuf will be nullified in the subroutine. Initially cbuf
 !> will get an allocation of 5000 bytes. realloc() will be used to
 !> increase the size if necessary. Users must free memory that cbuf
 !> points to when cbuf is no longer needed.
-!> @param[out] numfld Number of index records created.
-!> @param[out] mlen Total length of all index records.
-!> @param[out] iret Return code
+!> @param numfld Number of index records created.
+!> @param mlen Total length of all index records.
+!> @param iret Return code
 !> - 0 No error
 !> - 1 Not enough memory available to hold full index buffer.
 !> - 2 I/O error in read.
@@ -669,11 +805,17 @@ END SUBROUTINE GETGB2S
 !> - 5 Unidentified GRIB section encountered.
 !>
 !> @author Mark Iredell @date 1995-10-31
-SUBROUTINE IXGB2(LUGB, LSKIP, LGRIB, CBUF, NUMFLD, MLEN, IRET)
-  USE RE_ALLOC              ! NEEDED FOR SUBROUTINE REALLOC
+subroutine ix2gb2(lugb, lskip8, idxver, lgrib, cbuf, numfld, mlen, iret)
+  use re_alloc              ! needed for subroutine realloc
   implicit none
 
+  integer :: lugb
+  integer (kind = 8) :: lskip8
+  integer :: idxver, lgrib
   CHARACTER(LEN = 1), POINTER, DIMENSION(:) :: CBUF
+  integer :: numfld, mlen, iret
+  integer :: lskip
+  
   CHARACTER CVER, CDISC
   CHARACTER(LEN = 4) :: CTEMP
   INTEGER LOCLUS, LOCGDS, LENGDS, LOCBMS
@@ -681,7 +823,7 @@ SUBROUTINE IXGB2(LUGB, LSKIP, LGRIB, CBUF, NUMFLD, MLEN, IRET)
   integer :: linmax, ixskp
   integer :: mxspd, mxskp, mxsgd, mxsdr, mxsbm, mxlus
   integer :: mxlen, mxds, mxfld, mxbms
-  integer :: init, ixlus, lugb, lskip, lgrib, numfld, mlen, iret
+  integer :: init, ixlus
   integer :: ixsgd, ibread, ibskip, ilndrs, ilnpds, istat, ixds
   integer :: ixspd, ixfld, ixids, ixlen, ixsbm, ixsdr
   integer :: lbread, lensec, lensec1
@@ -693,6 +835,7 @@ SUBROUTINE IXGB2(LUGB, LSKIP, LGRIB, CBUF, NUMFLD, MLEN, IRET)
   CHARACTER CBREAD(LINMAX), CINDEX(LINMAX)
   CHARACTER CIDS(LINMAX), CGDS(LINMAX)
 
+  lskip = lskip8
   LOCLUS = 0
   IRET = 0
   MLEN = 0
@@ -811,7 +954,7 @@ SUBROUTINE IXGB2(LUGB, LSKIP, LGRIB, CBUF, NUMFLD, MLEN, IRET)
      ENDIF
      IBSKIP = IBSKIP + LENSEC
   ENDDO
-END SUBROUTINE IXGB2
+end subroutine ix2gb2
 
 !> Free all memory associated with the library.
 !>
diff --git a/tests/test_gbytec.F90 b/tests/test_gbytec.F90
index cfb49fb0..6064e2e2 100644
--- a/tests/test_gbytec.F90
+++ b/tests/test_gbytec.F90
@@ -11,6 +11,9 @@ program test_gbytec
   character*1 :: out5(5)
   character*1 :: out8(8)
   character*1 :: out10(10)
+  character*1 :: out16(16)
+  character*1 :: out32(32)
+  integer :: in4(4), in1(1)
   integer, parameter :: n = 1
   integer :: in(n)
   real :: r_in(n)
@@ -24,16 +27,22 @@ program test_gbytec
   integer :: nskip = 0
   integer :: i
   integer :: num
+  integer(kind = 4) :: in44(4), in44_1(4)
+  integer(kind = 8) :: in8(1), in8_1(1), in84(4), in84_1(4)
   
-  print *, 'Testing g2_gbytesc.f subroutines.'
+  print *, 'Testing g2_gbytesc.F90 subroutines.'
 
-  print *, 'Testing g2_sbytec()...'
+  print *, '   testing g2_sbytec()...'
   in(1) = 3
   out(1) = char(0)
   call g2_sbytec(out, in, iskip, nbits)
   if (ichar(out(1)) .ne. in(1)) stop 10
 
-  print *, 'Testing g2_sbytesc()...'
+  print *, '   testing g2_gbytec()...'
+  call g2_gbytec(out, in, iskip, nbits)
+  if (ichar(out(1)) .ne. in(1)) stop 11
+
+  print *, '   testing g2_sbytesc()...'
   in(1) = 3
   out(1) = char(0)
   call g2_sbytesc(out, in, iskip, nbits, nskip, n)
@@ -41,7 +50,7 @@ program test_gbytec
 
   ! This will pack the numbers 1 and 2 into the first two chars of the
   ! buffer. The rest of the output buffer will remain zeros.
-  print *, 'Testing g2_sbytesc() packing 2 values...'
+  print *, '   testing g2_sbytesc() packing 2 values...'
   in2(1) = 1
   in2(2) = 2
   do i = 1, 8
@@ -58,7 +67,7 @@ program test_gbytec
   end do
 
   ! Now pack 5 values into the 5 character array out5.
-  print *, 'Testing g2_sbytesc() packing 5 values...'
+  print *, '   testing g2_sbytesc() packing 5 values...'
   in5(1) = 1
   in5(2) = 2
   in5(3) = 3
@@ -76,7 +85,7 @@ program test_gbytec
 
   ! Now pack 5 values into the 10 character array out10. Skip every
   ! other byte in the output.
-  print *, 'Testing g2_sbytesc() packing 5 values, skipping every other byte...'
+  print *, '   testing g2_sbytesc() packing 5 values, skipping every other byte...'
   nbits = 8
   nskip = 0
   do i = 1, 10
@@ -88,32 +97,45 @@ program test_gbytec
      if (mod(i, 2) .gt. 0) then
         if (ichar(out10(i)) .ne. in5(int(i/2) + 1)) stop 51;
      else
-        if (ichar(out10(i)) .ne. 0) stop 50;
+        if (ichar(out10(i)) .ne. 0) stop 52;
      endif
   end do
 
-  print *, 'Testing g2_sbytec() with iskip of 1...'
+  print *, '   testing g2_sbytec() with iskip of 1...'
   in(1) = 1
   out(1) = char(0)
   call g2_sbytec(out, in, 1, 6)
-  ! print '(z2.2)', out(1)  
-  if (ichar(out(1)) .ne. 2) stop 20
+  if (ichar(out(1)) .ne. 2) stop 53
 
-  print *, 'Testing g2_sbytesc() with a small array...'
+  print *, '   testing g2_sbytesc() with a size 4 output array...'
   iskip = 0
   nbits = 32
   nskip = 0
   num = 1
   in(1) = 1
   call g2_sbytesc(out4, in, iskip, nbits, nskip, num)
-  if (ichar(out4(1)) .ne. 0 .and. ichar(out4(2)) .ne. 0 .and. ichar(out4(3)) .ne. 0 .and. ichar(out4(4)) .ne. 1) stop 50
-  !print '(z2.2)', out4(1)  
+  if (ichar(out4(1)) .ne. 0 .and. ichar(out4(2)) .ne. 0 .and. &
+       ichar(out4(3)) .ne. 0 .and. ichar(out4(4)) .ne. 1) stop 60
+
+  print *, '   now unpack into 4 ints with g2_gbytesc()...'
+  call g2_gbytesc(out4, in4, iskip, 8, 0, 4)
+  do i = 1, 4
+     if (i < 4) then
+        if (in4(i) .ne. 0) stop 61
+     else
+        if (in4(i) .ne. 1) stop 62
+     endif
+  end do
 
+  print *, '   now unpack into 1 int with g2_gbytesc()...'
+  call g2_gbytesc(out4, in1, iskip, 32, 0, 1)
+  if (in1(1) .ne. 1) stop 70
+  
   ! For this test to pass the -fallow-argument-mismatch flag must be
   ! used, because I am passing in a real array instead of an int array
   ! for the in parameter. This is how g2_sbytesc() is called in
   ! addfield.F90.
-  print *, 'Testing g2_sbytesc() with a real array (size 1) instead of an int array...'
+  print *, '   testing g2_sbytesc() with a real array (size 1) instead of an int array...'
   iskip = 0
   nbits = 32
   nskip = 0
@@ -122,14 +144,13 @@ program test_gbytec
   call g2_sbytesc(out4, r_in, iskip, nbits, nskip, num)
   ! Note that the 32-bit IEEE representation of 1.0 is 3f800000. The
   ! decimal for 3f is 63, the decimal for 80 is 128.
-  if (ichar(out4(1)) .ne. 63 .and. ichar(out4(2)) .ne. 128 .and. ichar(out4(3)) .ne. 0 .and. ichar(out4(4)) .ne. 0) stop 50
+  if (ichar(out4(1)) .ne. 63 .and. ichar(out4(2)) .ne. 128 .and. &
+       ichar(out4(3)) .ne. 0 .and. ichar(out4(4)) .ne. 0) stop 80
   ! print '(z2.2)', out4(1)  
-  ! print '(z2.2)', out4(2)  
-  ! print '(z2.2)', out4(3)  
-  ! print '(z2.2)', out4(4)
 
-  ! This test is the same as above, but does not require the -fallow-argument-mismatch flag.
-  print *, 'Testing g2_sbytesc() with a real array (size 1) instead of an int array, using transfer() intrinsic...'
+  ! This test is the same as above, but does not require the
+  ! -fallow-argument-mismatch flag.
+  print *, '   testing g2_sbytesc() with a size 1 real array instead of an int array, using transfer()...'
   iskip = 0
   nbits = 32
   nskip = 0
@@ -139,14 +160,14 @@ program test_gbytec
   call g2_sbytesc(out4, in, iskip, nbits, nskip, num)
   ! Note that the 32-bit IEEE representation of 1.0 is 3f800000. The
   ! decimal for 3f is 63, the decimal for 80 is 128.
-  if (ichar(out4(1)) .ne. 63 .and. ichar(out4(2)) .ne. 128 .and. ichar(out4(3)) .ne. 0 .and. ichar(out4(4)) .ne. 0) stop 50
-  ! print '(z2.2)', out4(1)  
+  if (ichar(out4(1)) .ne. 63 .and. ichar(out4(2)) .ne. 128 .and. &
+       ichar(out4(3)) .ne. 0 .and. ichar(out4(4)) .ne. 0) stop 90
 
   ! For this test to pass the -fallow-argument-mismatch flag must be
   ! used, because I am passing in a real array instead of an int array
   ! for the in parameter. This is how g2_sbytesc() is called in
   ! addfield.F90.
-  print *, 'Testing g2_sbytesc() with a real array instead of an int array...'
+  print *, '   testing g2_sbytesc() with a real array instead of an int array...'
   iskip = 0
   nbits = 32
   nskip = 0
@@ -156,12 +177,14 @@ program test_gbytec
   call g2_sbytesc(out8, r_in2, iskip, nbits, nskip, num)
   ! Note that the 32-bit IEEE representation of 1.0 is 3f800000. The
   ! decimal for 3f is 63, the decimal for 80 is 128.
-  if (ichar(out8(1)) .ne. 63 .and. ichar(out8(2)) .ne. 128 .and. ichar(out8(3)) .ne. 0 .and. ichar(out8(4)) .ne. 0) stop 50
-  if (ichar(out8(5)) .ne. 63 .and. ichar(out8(6)) .ne. 128 .and. ichar(out8(7)) .ne. 0 .and. ichar(out8(8)) .ne. 0) stop 50
+  if (ichar(out8(1)) .ne. 63 .and. ichar(out8(2)) .ne. 128 .and. &
+       ichar(out8(3)) .ne. 0 .and. ichar(out8(4)) .ne. 0) stop 100
+  if (ichar(out8(5)) .ne. 63 .and. ichar(out8(6)) .ne. 128 .and. &
+       ichar(out8(7)) .ne. 0 .and. ichar(out8(8)) .ne. 0) stop 110
   ! print '(z2.2)', out8(1)  
 
   ! This test is the same as above, but does not require the -fallow-argument-mismatch flag.
-  print *, 'Testing g2_sbytesc() with a real array instead of an int array, using transfer() intrinsic...'
+  print *, '   testing g2_sbytesc() with a real array instead of an int array, using transfer() intrinsic...'
   iskip = 0
   nbits = 32
   nskip = 0
@@ -172,10 +195,73 @@ program test_gbytec
   call g2_sbytesc(out8, in2, iskip, nbits, nskip, num)
   ! Note that the 32-bit IEEE representation of 1.0 is 3f800000. The
   ! decimal for 3f is 63, the decimal for 80 is 128.
-  if (ichar(out4(1)) .ne. 63 .and. ichar(out4(2)) .ne. 128 .and. ichar(out4(3)) .ne. 0 .and. ichar(out4(4)) .ne. 0) stop 50
-  if (ichar(out8(5)) .ne. 63 .and. ichar(out8(6)) .ne. 128 .and. ichar(out8(7)) .ne. 0 .and. ichar(out8(8)) .ne. 0) stop 50
+  if (ichar(out4(1)) .ne. 63 .and. ichar(out4(2)) .ne. 128 .and. &
+       ichar(out4(3)) .ne. 0 .and. ichar(out4(4)) .ne. 0) stop 120
+  if (ichar(out8(5)) .ne. 63 .and. ichar(out8(6)) .ne. 128 .and. &
+       ichar(out8(7)) .ne. 0 .and. ichar(out8(8)) .ne. 0) stop 130
   ! print '(z2.2)', out4(1)  
 
+  print *, '   testing g2_sbytec() with 64-bit int...'
+  in8(1) = 1
+  do i = 1, 8
+     out8(i) = char(0)
+  end do
+  call g2_sbytec(out8, in8, iskip, 64)
+  do i = 1, 8
+     !print '(z2.2)', out8(i)
+     if (i .lt. 8) then
+        if (ichar(out8(i)) .ne. 0) stop 140
+     else
+        if (ichar(out8(i)) .ne. 1) stop 140
+     endif
+  end do
+
+  print *, '   now unpack into 1 64-bit int with g2_gbytesc()...'
+  in8_1(1) = 0
+  call g2_gbytesc(out8, in8_1, iskip, 64, 0, 1)
+  if (in8_1(1) .ne. in8(1)) stop 150
+
+  print *, '   testing g2_sbytec() with 32-bit int array of size 4...'
+  do i = 1, 4
+     in44(i) = 1
+  end do
+  do i = 1, 16
+     out16(i) = char(0)
+  end do
+  call g2_sbytesc(out16, in44, iskip, 32, 0, 4)
+  do i = 1, 16
+     print '(i3, x, z2.2)', i, out16(i)
+  end do
+  
+  print *, '   now unpack into 4 32-bit ints with g2_gbytesc()...'
+  do i = 1, 4
+     in44_1(i) = 0
+  end do
+  call g2_gbytesc(out16, in44_1, iskip, 32, 0, 4)
+  do i = 1, 4
+     if (in44_1(i) .ne. in44(i)) stop 160
+  end do
+
+  print *, '   testing g2_sbytec() with 64-bit int array of size 4...'
+  do i = 1, 4
+     in84(i) = 1
+  end do
+  do i = 1, 32
+     out32(i) = char(0)
+  end do
+  print *, in84
+  call g2_sbytesc(out32, in84, iskip, 64, 0, 4)
+  do i = 1, 32
+     print '(i3, x, z2.2)', i, out32(i)
+  end do
+
+  print *, '   now unpack into 4 64-bit ints with g2_gbytesc()...'
+  do i = 1, 4
+     in84_1(i) = 0
+  end do
+  call g2_gbytesc(out32, in84_1, iskip, 64, 0, 4)
+  print *, in84_1
+
   print *, 'SUCCESS!'
 
 end program test_gbytec
diff --git a/tests/test_getg2ir.F90 b/tests/test_getg2ir.F90
index 268817ac..409cfe03 100644
--- a/tests/test_getg2ir.F90
+++ b/tests/test_getg2ir.F90
@@ -10,6 +10,7 @@ program test_getg2ir
   integer :: lugb = 3
   character(len=1), pointer, dimension(:) :: cbuf(:)
   integer :: msk1, msk2, mnum
+  integer (kind = 8) :: msk18, msk28
   integer :: nlen, nnum, nmess, iret
 
   interface
@@ -20,58 +21,79 @@ subroutine getg2ir(lugb, msk1, msk2, mnum, cbuf, nlen, nnum, nmess, iret)
      end subroutine getg2ir
   end interface
 
+  interface
+     subroutine getg2i2r(lugb, msk18, msk28, mnum, idxver, cbuf, nlen, &
+          nnum, nmess, iret)
+       character(len = 1), pointer, dimension(:) :: cbuf
+       integer, intent(in) :: lugb
+       integer (kind = 8), intent(in) :: msk18, msk28
+       integer, intent(in) :: mnum, idxver
+       integer, intent(out) :: nlen, nnum, nmess, iret
+     end subroutine getg2i2r
+  end interface
   integer :: index_rec_len, b2s_message, b2s_lus, b2s_gds, b2s_pds, b2s_drs, b2s_bms, b2s_data
   integer :: total_bytes, grib_version, discipline, field_number
+  integer :: idxver, t
+
+  print *, 'Testing the getg2ir()/getg2i2r() subroutines.'
 
-  print *, 'Testing the getg2ir() subroutine - expect and ignore error messages during test...'
+  do t = 1, 2
+     ! Open a real GRIB2 file.
+     print *, 'Indexing a real GRIB2 file, trial ', t
+     call baopenr(lugb, "data/WW3_Regional_US_West_Coast_20220718_0000.grib2", iret)
+     if (iret .ne. 0) stop 100
 
-  ! Open a real GRIB2 file.
-  print *, 'Indexing a real GRIB2 file...'
-  call baopenr(lugb, "data/WW3_Regional_US_West_Coast_20220718_0000.grib2", iret)
-  if (iret .ne. 0) stop 100
+     msk1 = 1000
+     msk2 = 1000
+     msk18 = 1000
+     msk28 = 1000
+     mnum = 0
+     if (t .eq. 1) then
+        call getg2ir(lugb, msk1, msk2, mnum, cbuf, nlen, nnum, nmess, iret)
+     else
+        idxver = 1
+        call getg2i2r(lugb, msk18, msk28, mnum, idxver, cbuf, nlen, nnum, nmess, iret)
+     endif
+     if (iret .ne. 0) stop 101
+     if (nlen .ne. 137600 .or. nnum .ne. 688 .or. nmess .ne. 688) stop 102
+     print *, 'nlen, nnum, nmess: ', nlen, nnum, nmess
 
-  msk1 = 1000
-  msk2 = 1000
-  mnum = 0
-  call getg2ir(lugb, msk1, msk2, mnum, cbuf, nlen, nnum, nmess, iret)
-  if (iret .ne. 0) stop 101
-  if (nlen .ne. 137600 .or. nnum .ne. 688 .or. nmess .ne. 688) stop 102
-  print *, 'nlen, nnum, nmess: ', nlen, nnum, nmess
-  
-  ! Break out the index record into component values.
-  call g2_gbytec(cbuf, index_rec_len, 0, 8 * 4)
-  if (index_rec_len .ne. 200) stop 105
-  call g2_gbytec(cbuf, b2s_message, 8 * 4, 8 * 4)
-  if (b2s_message .ne. 202) stop 106
-  call g2_gbytec(cbuf, b2s_lus, 8 * 8, 8 * 4)
-  if (b2s_lus .ne. 0) stop 107
-  call g2_gbytec(cbuf, b2s_gds, 8 * 12, 8 * 4)
-  if (b2s_gds .ne. 37) stop 108
-  call g2_gbytec(cbuf, b2s_pds, 8 * 16, 8 * 4)
-  if (b2s_pds .ne. 109) stop 109
-  call g2_gbytec(cbuf, b2s_drs, 8 * 20, 8 * 4)
-  if (b2s_drs .ne. 143) stop 110
-  call g2_gbytec(cbuf, b2s_bms, 8 * 24, 8 * 4)
-  if (b2s_bms .ne. 166) stop 111
-  call g2_gbytec(cbuf, b2s_data, 8 * 28, 8 * 4)
-  if (b2s_data .ne. 4721) stop 112
-  call g2_gbytec(cbuf, total_bytes, 8 * 32, 8 * 8)
-  if (total_bytes .ne. 11183) stop 113
-  call g2_gbytec(cbuf, grib_version, 8 * 40, 8 * 1)
-  if (grib_version .ne. 2) stop 113
-  call g2_gbytec(cbuf, discipline, 8 * 41, 8 * 1)
-  if (discipline .ne. 10) stop 113
-  call g2_gbytec(cbuf, field_number, 8 * 42, 8 * 2)
-  if (field_number .ne. 1) stop 113
-  print *, 'index_rec_len = ', index_rec_len, ' b2s_message = ', b2s_message
-  print *, 'b2s_lus, b2s_gds, b2s_pds, b2s_drs, b2s_bms, b2s_data: ', b2s_lus, b2s_gds, b2s_pds, b2s_drs, b2s_bms, b2s_data
-  print *, 'total_bytes, grib_version, discipline, field_number: ', total_bytes, grib_version, discipline, field_number
+     ! Break out the index record into component values.
+     call g2_gbytec(cbuf, index_rec_len, 0, 8 * 4)
+     if (index_rec_len .ne. 200) stop 105
+     call g2_gbytec(cbuf, b2s_message, 8 * 4, 8 * 4)
+     if (b2s_message .ne. 202) stop 106
+     call g2_gbytec(cbuf, b2s_lus, 8 * 8, 8 * 4)
+     if (b2s_lus .ne. 0) stop 107
+     call g2_gbytec(cbuf, b2s_gds, 8 * 12, 8 * 4)
+     if (b2s_gds .ne. 37) stop 108
+     call g2_gbytec(cbuf, b2s_pds, 8 * 16, 8 * 4)
+     if (b2s_pds .ne. 109) stop 109
+     call g2_gbytec(cbuf, b2s_drs, 8 * 20, 8 * 4)
+     if (b2s_drs .ne. 143) stop 110
+     call g2_gbytec(cbuf, b2s_bms, 8 * 24, 8 * 4)
+     if (b2s_bms .ne. 166) stop 111
+     call g2_gbytec(cbuf, b2s_data, 8 * 28, 8 * 4)
+     if (b2s_data .ne. 4721) stop 112
+     call g2_gbytec(cbuf, total_bytes, 8 * 32, 8 * 8)
+     if (total_bytes .ne. 11183) stop 113
+     call g2_gbytec(cbuf, grib_version, 8 * 40, 8 * 1)
+     if (grib_version .ne. 2) stop 113
+     call g2_gbytec(cbuf, discipline, 8 * 41, 8 * 1)
+     if (discipline .ne. 10) stop 113
+     call g2_gbytec(cbuf, field_number, 8 * 42, 8 * 2)
+     if (field_number .ne. 1) stop 113
+     print *, 'index_rec_len = ', index_rec_len, ' b2s_message = ', b2s_message
+     print *, 'b2s_lus, b2s_gds, b2s_pds, b2s_drs, b2s_bms, b2s_data: ', b2s_lus, b2s_gds, b2s_pds, b2s_drs, b2s_bms, b2s_data
+     print *, 'total_bytes, grib_version, discipline, field_number: ', total_bytes, grib_version, discipline, field_number
 
-  deallocate(cbuf)
-  
-  call baclose(lugb, iret)
-  if (iret .ne. 0) stop 199
+     deallocate(cbuf)
+     cbuf => null()
 
+     call baclose(lugb, iret)
+     if (iret .ne. 0) stop 199
+     print *, 'OK!'
+  end do
   print *, 'SUCCESS!...'
 
 end program test_getg2ir