diff --git a/include/armadillo_bits/Cube_meat.hpp b/include/armadillo_bits/Cube_meat.hpp
index 9b68ccdc..6dc19ce9 100644
--- a/include/armadillo_bits/Cube_meat.hpp
+++ b/include/armadillo_bits/Cube_meat.hpp
@@ -296,7 +296,7 @@ inline
 void
 Cube<eT>::init_cold()
   {
-  arma_debug_sigprint( arma_str::format("n_rows = %u, n_cols = %u, n_slices = %u") % n_rows % n_cols % n_slices );
+  arma_debug_sigprint( arma_str::format("n_rows: %u; n_cols: %u; n_slices: %u") % n_rows % n_cols % n_slices );
   
   #if defined(ARMA_64BIT_WORD)
     const char* error_message = "Cube::init(): requested size is too large";
@@ -340,7 +340,7 @@ inline
 void
 Cube<eT>::init_warm(const uword in_n_rows, const uword in_n_cols, const uword in_n_slices)
   {
-  arma_debug_sigprint( arma_str::format("in_n_rows = %u, in_n_cols = %u, in_n_slices = %u") % in_n_rows % in_n_cols % in_n_slices );
+  arma_debug_sigprint( arma_str::format("in_n_rows: %u; in_n_cols: %u; in_n_slices: %u") % in_n_rows % in_n_cols % in_n_slices );
   
   if( (n_rows == in_n_rows) && (n_cols == in_n_cols) && (n_slices == in_n_slices) )  { return; }
   
diff --git a/include/armadillo_bits/Mat_meat.hpp b/include/armadillo_bits/Mat_meat.hpp
index 178df007..aec54271 100644
--- a/include/armadillo_bits/Mat_meat.hpp
+++ b/include/armadillo_bits/Mat_meat.hpp
@@ -294,7 +294,7 @@ inline
 void
 Mat<eT>::init_cold()
   {
-  arma_debug_sigprint( arma_str::format("n_rows = %u, n_cols = %u") % n_rows % n_cols );
+  arma_debug_sigprint( arma_str::format("n_rows: %u; n_cols: %u") % n_rows % n_cols );
   
   // ensure that n_elem can hold the result of (n_rows * n_cols)
   
@@ -337,7 +337,7 @@ inline
 void
 Mat<eT>::init_warm(uword in_n_rows, uword in_n_cols)
   {
-  arma_debug_sigprint( arma_str::format("in_n_rows = %u, in_n_cols = %u") % in_n_rows % in_n_cols );
+  arma_debug_sigprint( arma_str::format("in_n_rows: %u; in_n_cols: %u") % in_n_rows % in_n_cols );
   
   if( (n_rows == in_n_rows) && (n_cols == in_n_cols) )  { return; }
   
diff --git a/include/armadillo_bits/config.hpp b/include/armadillo_bits/config.hpp
index 9cba2fa5..93b25ef9 100644
--- a/include/armadillo_bits/config.hpp
+++ b/include/armadillo_bits/config.hpp
@@ -201,7 +201,13 @@
 //// Uncomment the above line to see the function traces of how Armadillo evaluates expressions.
 //// This is mainly useful for debugging of the library.
 
-#if defined(ARMA_DEBUG) || defined(ARMA_EXTRA_DEBUG)
+#if defined(ARMA_EXTRA_DEBUG)
+  // for compatibility with earlier versions of Armadillo
+  #undef  ARMA_DEBUG
+  #define ARMA_DEBUG
+#endif
+
+#if defined(ARMA_DEBUG)
   #undef  ARMA_DONT_CHECK_CONFORMANCE
   #undef  ARMA_DONT_CHECK_NONFINITE
   #undef  ARMA_WARN_LEVEL
diff --git a/include/armadillo_bits/config.hpp.cmake b/include/armadillo_bits/config.hpp.cmake
index f1d536a9..a1ad9db1 100644
--- a/include/armadillo_bits/config.hpp.cmake
+++ b/include/armadillo_bits/config.hpp.cmake
@@ -201,7 +201,13 @@
 //// Uncomment the above line to see the function traces of how Armadillo evaluates expressions.
 //// This is mainly useful for debugging of the library.
 
-#if defined(ARMA_DEBUG) || defined(ARMA_EXTRA_DEBUG)
+#if defined(ARMA_EXTRA_DEBUG)
+  // for compatibility with earlier versions of Armadillo
+  #undef  ARMA_DEBUG
+  #define ARMA_DEBUG
+#endif
+
+#if defined(ARMA_DEBUG)
   #undef  ARMA_DONT_CHECK_CONFORMANCE
   #undef  ARMA_DONT_CHECK_NONFINITE
   #undef  ARMA_WARN_LEVEL
diff --git a/include/armadillo_bits/debug.hpp b/include/armadillo_bits/debug.hpp
index f96e2585..299654c2 100644
--- a/include/armadillo_bits/debug.hpp
+++ b/include/armadillo_bits/debug.hpp
@@ -317,7 +317,7 @@ inline
 void
 arma_thisprint(const void* this_ptr)
   {
-  get_cerr_stream() << " [this = " << this_ptr << ']' << std::endl;
+  get_cerr_stream() << " [this: " << this_ptr << ']' << std::endl;
   }
 
 
@@ -1369,7 +1369,7 @@ arma_assert_atlas_size(const T1& A, const T2& B)
 
 
 
-#if defined(ARMA_DEBUG) || defined(ARMA_EXTRA_DEBUG)
+#if defined(ARMA_DEBUG)
   
   #define arma_debug_sigprint       arma_sigprint(ARMA_FNSIG); arma_bktprint
   #define arma_debug_sigprint_this  arma_sigprint(ARMA_FNSIG); arma_thisprint
diff --git a/include/armadillo_bits/field_meat.hpp b/include/armadillo_bits/field_meat.hpp
index 0cc4acd7..de75ac2a 100644
--- a/include/armadillo_bits/field_meat.hpp
+++ b/include/armadillo_bits/field_meat.hpp
@@ -205,7 +205,7 @@ inline
 field<oT>&
 field<oT>::set_size(const uword n_elem_in)
   {
-  arma_debug_sigprint(arma_str::format("n_elem_in = %u") % n_elem_in);
+  arma_debug_sigprint(arma_str::format("n_elem_in: %u") % n_elem_in);
   
   init(n_elem_in, 1);
   
@@ -220,7 +220,7 @@ inline
 field<oT>&
 field<oT>::set_size(const uword n_rows_in, const uword n_cols_in)
   {
-  arma_debug_sigprint(arma_str::format("n_rows_in = %u, n_cols_in = %u") % n_rows_in % n_cols_in);
+  arma_debug_sigprint(arma_str::format("n_rows_in: %u; n_cols_in: %u") % n_rows_in % n_cols_in);
   
   init(n_rows_in, n_cols_in);
   
@@ -235,7 +235,7 @@ inline
 field<oT>&
 field<oT>::set_size(const uword n_rows_in, const uword n_cols_in, const uword n_slices_in)
   {
-  arma_debug_sigprint(arma_str::format("n_rows_in = %u, n_cols_in = %u, n_slices_in = %u") % n_rows_in % n_cols_in % n_slices_in);
+  arma_debug_sigprint(arma_str::format("n_rows_in: %u; n_cols_in: %u; n_slices_in: %u") % n_rows_in % n_cols_in % n_slices_in);
   
   init(n_rows_in, n_cols_in, n_slices_in);
   
@@ -2014,7 +2014,7 @@ inline
 void
 field<oT>::init(const uword n_rows_in, const uword n_cols_in, const uword n_slices_in)
   {
-  arma_debug_sigprint( arma_str::format("n_rows_in = %u, n_cols_in = %u, n_slices_in = %u") % n_rows_in % n_cols_in % n_slices_in );
+  arma_debug_sigprint( arma_str::format("n_rows_in: %u; n_cols_in: %u; n_slices_in: %u") % n_rows_in % n_cols_in % n_slices_in );
   
   #if defined(ARMA_64BIT_WORD)
     const char* error_message = "field::init(): requested size is too large";
@@ -2075,7 +2075,7 @@ inline
 void
 field<oT>::delete_objects()
   {
-  arma_debug_sigprint( arma_str::format("n_elem = %u") % n_elem );
+  arma_debug_sigprint( arma_str::format("n_elem: %u") % n_elem );
   
   for(uword i=0; i<n_elem; ++i)
     {
@@ -2094,7 +2094,7 @@ inline
 void
 field<oT>::create_objects()
   {
-  arma_debug_sigprint( arma_str::format("n_elem = %u") % n_elem );
+  arma_debug_sigprint( arma_str::format("n_elem: %u") % n_elem );
   
   for(uword i=0; i<n_elem; ++i)  { mem[i] = new oT; }
   }
diff --git a/include/armadillo_bits/fn_as_scalar.hpp b/include/armadillo_bits/fn_as_scalar.hpp
index 7e3a551b..5509f844 100644
--- a/include/armadillo_bits/fn_as_scalar.hpp
+++ b/include/armadillo_bits/fn_as_scalar.hpp
@@ -305,7 +305,7 @@ as_scalar(const Glue<T1, T2, glue_times>& X, const typename arma_not_cx<typename
   
   constexpr uword N_mat = 1 + depth_lhs< glue_times, Glue<T1,T2,glue_times> >::num;
   
-  arma_debug_print(arma_str::format("N_mat = %u") % N_mat);
+  arma_debug_print(arma_str::format("N_mat: %u") % N_mat);
   
   return as_scalar_redirect<N_mat>::apply(X);
   }
diff --git a/include/armadillo_bits/glue_times_meat.hpp b/include/armadillo_bits/glue_times_meat.hpp
index 5bf6b5f5..6eed7d39 100644
--- a/include/armadillo_bits/glue_times_meat.hpp
+++ b/include/armadillo_bits/glue_times_meat.hpp
@@ -483,7 +483,7 @@ glue_times::apply(Mat<typename T1::elem_type>& out, const Glue<T1,T2,glue_times>
   
   constexpr uword N_mat = 1 + depth_lhs< glue_times, Glue<T1,T2,glue_times> >::num;
   
-  arma_debug_print(arma_str::format("N_mat = %u") % N_mat);
+  arma_debug_print(arma_str::format("N_mat: %u") % N_mat);
   
   glue_times_redirect<N_mat>::apply(out, X);
   }
diff --git a/include/armadillo_bits/subview_cube_meat.hpp b/include/armadillo_bits/subview_cube_meat.hpp
index 7969b3fd..6edd431b 100644
--- a/include/armadillo_bits/subview_cube_meat.hpp
+++ b/include/armadillo_bits/subview_cube_meat.hpp
@@ -1712,7 +1712,7 @@ subview_cube<eT>::extract(Cube<eT>& out, const subview_cube<eT>& in)
   const uword n_cols   = in.n_cols;
   const uword n_slices = in.n_slices;
   
-  arma_debug_print(arma_str::format("out.n_rows = %u   out.n_cols = %u    out.n_slices = %u    in.m.n_rows = %u   in.m.n_cols = %u   in.m.n_slices = %u") % out.n_rows % out.n_cols % out.n_slices % in.m.n_rows % in.m.n_cols % in.m.n_slices);
+  arma_debug_print(arma_str::format("out.n_rows: %u; out.n_cols: %u; out.n_slices: %u; in.m.n_rows: %u; in.m.n_cols: %u; in.m.n_slices: %u") % out.n_rows % out.n_cols % out.n_slices % in.m.n_rows % in.m.n_cols % in.m.n_slices);
   
   if( (in.aux_row1 == 0) && (n_rows == in.m.n_rows) )
     {
diff --git a/include/armadillo_bits/subview_field_meat.hpp b/include/armadillo_bits/subview_field_meat.hpp
index 5b427a57..7a402e19 100644
--- a/include/armadillo_bits/subview_field_meat.hpp
+++ b/include/armadillo_bits/subview_field_meat.hpp
@@ -525,7 +525,7 @@ subview_field<oT>::extract(field<oT>& actual_out, const subview_field<oT>& in)
   
   out.set_size(n_rows, n_cols, n_slices);
   
-  arma_debug_print(arma_str::format("out.n_rows = %u   out.n_cols = %u   out.n_slices = %u    in.m.n_rows = %u  in.m.n_cols = %u  in.m.n_slices = %u") % out.n_rows % out.n_cols % out.n_slices % in.f.n_rows % in.f.n_cols % in.f.n_slices);
+  arma_debug_print(arma_str::format("out.n_rows: %u; out.n_cols: %u; out.n_slices: %u; n.m.n_rows: %u; in.m.n_cols: %u; in.m.n_slices: %u") % out.n_rows % out.n_cols % out.n_slices % in.f.n_rows % in.f.n_cols % in.f.n_slices);
   
   if(n_slices == 1)
     {
diff --git a/include/armadillo_bits/subview_meat.hpp b/include/armadillo_bits/subview_meat.hpp
index 5079c6b2..6535eb9b 100644
--- a/include/armadillo_bits/subview_meat.hpp
+++ b/include/armadillo_bits/subview_meat.hpp
@@ -1600,7 +1600,7 @@ subview<eT>::extract(Mat<eT>& out, const subview<eT>& in)
   const uword n_rows = in.n_rows;  // number of rows in the subview
   const uword n_cols = in.n_cols;  // number of columns in the subview
   
-  arma_debug_print(arma_str::format("out.n_rows = %u   out.n_cols = %u    in.m.n_rows = %u  in.m.n_cols = %u") % out.n_rows % out.n_cols % in.m.n_rows % in.m.n_cols );
+  arma_debug_print(arma_str::format("out.n_rows: %u; out.n_cols: %u; in.m.n_rows: %u; in.m.n_cols: %u") % out.n_rows % out.n_cols % in.m.n_rows % in.m.n_cols );
   
   
   if(in.is_vec())