diff --git a/examples/symba_swifter_comparison/1pl_1pl_encounter/init_cond.py b/examples/symba_swifter_comparison/1pl_1pl_encounter/init_cond.py
index 20be5a433..ece9101e0 100755
--- a/examples/symba_swifter_comparison/1pl_1pl_encounter/init_cond.py
+++ b/examples/symba_swifter_comparison/1pl_1pl_encounter/init_cond.py
@@ -131,8 +131,7 @@
 
 plfile = FortranFile(swiftest_pl, 'w')
 plfile.write_record(npl)
-
-plfile.write_record(np.array([plid1, plid2]))
+plfile.write_record(np.array([plid1, plid2], dtype=np.int32))
 plfile.write_record(np.vstack([p_pl1[0],p_pl2[0]]))
 plfile.write_record(np.vstack([p_pl1[1],p_pl2[1]]))
 plfile.write_record(np.vstack([p_pl1[2],p_pl2[2]]))
diff --git a/examples/symba_swifter_comparison/1pl_1pl_encounter/pl.swiftest.in b/examples/symba_swifter_comparison/1pl_1pl_encounter/pl.swiftest.in
index d8da7a92a..1bda0535d 100644
Binary files a/examples/symba_swifter_comparison/1pl_1pl_encounter/pl.swiftest.in and b/examples/symba_swifter_comparison/1pl_1pl_encounter/pl.swiftest.in differ
diff --git a/src/io/io.f90 b/src/io/io.f90
index 2900fc7f4..d2791aa92 100644
--- a/src/io/io.f90
+++ b/src/io/io.f90
@@ -839,7 +839,7 @@ module subroutine io_read_frame_body(self, iu, param, form, ierr)
       integer(I4B),               intent(out)   :: ierr   !! Error code
 
       associate(n => self%nbody)
-         read(iu, iostat=ierr, err=100) self%id(1:n)
+         read(iu, iostat=ierr, err=100) self%id(:)
          !read(iu, iostat=ierr, err=100) self%name(1:n)
          select case (form)
          case (EL) 
@@ -849,33 +849,33 @@ module subroutine io_read_frame_body(self, iu, param, form, ierr)
             if (.not.allocated(self%capom)) allocate(self%capom(n))
             if (.not.allocated(self%omega)) allocate(self%omega(n))
             if (.not.allocated(self%capm))  allocate(self%capm(n))
-            read(iu, iostat=ierr, err=100) self%a(1:n)
-            read(iu, iostat=ierr, err=100) self%e(1:n)
-            read(iu, iostat=ierr, err=100) self%inc(1:n)
+            read(iu, iostat=ierr, err=100) self%a(:)
+            read(iu, iostat=ierr, err=100) self%e(:)
+            read(iu, iostat=ierr, err=100) self%inc(:)
             read(iu, iostat=ierr, err=100) self%capom(:)
             read(iu, iostat=ierr, err=100) self%omega(:)
             read(iu, iostat=ierr, err=100) self%capm(:)
          case (XV)
-            read(iu, iostat=ierr, err=100) self%xh(1, 1:n)
-            read(iu, iostat=ierr, err=100) self%xh(2, 1:n)
-            read(iu, iostat=ierr, err=100) self%xh(3, 1:n)
-            read(iu, iostat=ierr, err=100) self%vh(1, 1:n)
-            read(iu, iostat=ierr, err=100) self%vh(2, 1:n)
-            read(iu, iostat=ierr, err=100) self%vh(3, 1:n)
+            read(iu, iostat=ierr, err=100) self%xh(1, :)
+            read(iu, iostat=ierr, err=100) self%xh(2, :)
+            read(iu, iostat=ierr, err=100) self%xh(3, :)
+            read(iu, iostat=ierr, err=100) self%vh(1, :)
+            read(iu, iostat=ierr, err=100) self%vh(2, :)
+            read(iu, iostat=ierr, err=100) self%vh(3, :)
          end select
          select type(pl => self)  
          class is (swiftest_pl)  ! Additional output if the passed polymorphic object is a massive body
-            read(iu, iostat=ierr, err=100) pl%Gmass(1:n)
-            pl%mass(1:n) = pl%Gmass / param%GU 
-            if (param%lrhill_present) read(iu, iostat=ierr, err=100) pl%rhill(1:n)
-            read(iu, iostat=ierr, err=100) pl%radius(1:n)
+            read(iu, iostat=ierr, err=100) pl%Gmass(:)
+            pl%mass(:) = pl%Gmass(:) / param%GU 
+            if (param%lrhill_present) read(iu, iostat=ierr, err=100) pl%rhill(:)
+            read(iu, iostat=ierr, err=100) pl%radius(:)
             if (param%lrotation) then
-               read(iu, iostat=ierr, err=100) pl%rot(1, 1:n)
-               read(iu, iostat=ierr, err=100) pl%rot(2, 1:n)
-               read(iu, iostat=ierr, err=100) pl%rot(3, 1:n)
-               read(iu, iostat=ierr, err=100) pl%Ip(1, 1:n)
-               read(iu, iostat=ierr, err=100) pl%Ip(2, 1:n)
-               read(iu, iostat=ierr, err=100) pl%Ip(3, 1:n)
+               read(iu, iostat=ierr, err=100) pl%rot(1, :)
+               read(iu, iostat=ierr, err=100) pl%rot(2, :)
+               read(iu, iostat=ierr, err=100) pl%rot(3, :)
+               read(iu, iostat=ierr, err=100) pl%Ip(1, :)
+               read(iu, iostat=ierr, err=100) pl%Ip(2, :)
+               read(iu, iostat=ierr, err=100) pl%Ip(3, :)
             end if
             if (param%ltides) then
                read(iu, iostat=ierr, err=100) pl%k2(1:n)