diff --git a/inst/@sym/and.m b/inst/@sym/and.m
index a6b24c37b..7a4506b57 100644
--- a/inst/@sym/and.m
+++ b/inst/@sym/and.m
@@ -1,4 +1,5 @@
-%% Copyright (C) 2014-2016, 2018 Colin B. Macdonald
+%% SPDX-License-Identifier: AGPL-3.0-or-later
+%% Copyright (C) 2014-2016, 2018, 2024 Colin B. Macdonald
 %%
 %% This file is part of OctSymPy.
 %%
@@ -59,7 +60,7 @@
 %! assert (isequal (t & t, t))
 
 %!test
-%! % mix wih nonsym
+%! % mix with nonsym
 %! assert (isequal (t & false, f))
 %! assert (isequal (t & true, t))
 %! assert (isequal (t & 0, f))
diff --git a/inst/@sym/coeffs.m b/inst/@sym/coeffs.m
index 21839cf89..682ef4ea9 100644
--- a/inst/@sym/coeffs.m
+++ b/inst/@sym/coeffs.m
@@ -1,4 +1,5 @@
-%% Copyright (C) 2014-2017, 2019, 2022-2023 Colin B. Macdonald
+%% SPDX-License-Identifier: AGPL-3.0-or-later
+%% Copyright (C) 2014-2017, 2019, 2022-2024 Colin B. Macdonald
 %%
 %% This file is part of OctSymPy.
 %%
@@ -164,7 +165,7 @@
     c = fliplr(c);
   end
 
-  % if nargout == 1, its simplier to use 'p.coeffs()'
+  % if nargout == 1, its simpler to use 'p.coeffs()'
 end
 
 
diff --git a/inst/@sym/eq.m b/inst/@sym/eq.m
index b4fce6ee6..0591fd7b1 100644
--- a/inst/@sym/eq.m
+++ b/inst/@sym/eq.m
@@ -1,4 +1,5 @@
-%% Copyright (C) 2014, 2016 Colin B. Macdonald
+%% SPDX-License-Identifier: AGPL-3.0-or-later
+%% Copyright (C) 2014, 2016, 2024 Colin B. Macdonald
 %%
 %% This file is part of OctSymPy.
 %%
@@ -82,6 +83,7 @@
 %% @seealso{@@sym/logical, @@sym/isAlways, @@sym/isequal, @@sym/ne, @@sym/le}
 %% @end defop
 
+
 function t = eq(x, y)
 
   if (nargin ~= 2)
@@ -118,7 +120,7 @@
 %! assert (isa (e, 'sym'))
 
 %!test
-%! % ... except of course via cancelation
+%! % ... except of course via cancellation
 %! syms x
 %! e = x - x == 0;
 %! assert (logical (e))
diff --git a/inst/@sym/ezmesh.m b/inst/@sym/ezmesh.m
index 499422e21..116d8719d 100644
--- a/inst/@sym/ezmesh.m
+++ b/inst/@sym/ezmesh.m
@@ -1,4 +1,5 @@
-%% Copyright (C) 2019, 2023 Colin B. Macdonald
+%% SPDX-License-Identifier: AGPL-3.0-or-later
+%% Copyright (C) 2019, 2023-2024 Colin B. Macdonald
 %%
 %% This file is part of OctSymPy.
 %%
@@ -74,7 +75,7 @@
   for i = firstpotsym:nargin
     if (isa(varargin{i}, 'sym'))
       if (i < firstpotsym + maxnumsym)
-        % one of the fcns to plot, covert to handle fcn
+        % one of the fcns to plot, convert to handle fcn
 
         % Each is function of one var, and its the same var for all
         thissym = symvar(varargin{i});
diff --git a/inst/@sym/ezplot3.m b/inst/@sym/ezplot3.m
index ebb1e35f6..44cd916b8 100644
--- a/inst/@sym/ezplot3.m
+++ b/inst/@sym/ezplot3.m
@@ -1,4 +1,5 @@
-%% Copyright (C) 2014-2016, 2023 Colin B. Macdonald
+%% SPDX-License-Identifier: AGPL-3.0-or-later
+%% Copyright (C) 2014-2016, 2023-2024 Colin B. Macdonald
 %%
 %% This file is part of OctSymPy.
 %%
@@ -59,7 +60,7 @@
   for i = firstpotsym:nargin
     if (isa(varargin{i}, 'sym'))
       if (i < firstpotsym + maxnumsym)
-        % one of the fcns to plot, covert to handle fcn
+        % one of the fcns to plot, convert to handle fcn
 
         % Each is function of one var, and its the same var for all
         thissym = symvar(varargin{i});
diff --git a/inst/@sym/ezsurf.m b/inst/@sym/ezsurf.m
index 00396b1f6..a2c7333bd 100644
--- a/inst/@sym/ezsurf.m
+++ b/inst/@sym/ezsurf.m
@@ -1,4 +1,5 @@
-%% Copyright (C) 2016-2017, 2019, 2023 Colin B. Macdonald
+%% SPDX-License-Identifier: AGPL-3.0-or-later
+%% Copyright (C) 2016-2017, 2019, 2023-2024 Colin B. Macdonald
 %%
 %% This file is part of OctSymPy.
 %%
@@ -74,7 +75,7 @@
   for i = firstpotsym:nargin
     if (isa(varargin{i}, 'sym'))
       if (i < firstpotsym + maxnumsym)
-        % one of the fcns to plot, covert to handle fcn
+        % one of the fcns to plot, convert to handle fcn
 
         % Each is function of one var, and its the same var for all
         thissym = symvar(varargin{i});
diff --git a/inst/@sym/fourier.m b/inst/@sym/fourier.m
index 64e02f729..5a1c7732b 100644
--- a/inst/@sym/fourier.m
+++ b/inst/@sym/fourier.m
@@ -1,4 +1,5 @@
-%% Copyright (C) 2014-2016, 2019 Colin B. Macdonald
+%% SPDX-License-Identifier: AGPL-3.0-or-later
+%% Copyright (C) 2014-2016, 2019, 2024 Colin B. Macdonald
 %% Copyright (C) 2015-2016 Andrés Prieto
 %% Copyright (C) 2015 Alexander Misel
 %%
@@ -176,7 +177,7 @@
 
 
 %!test
-%! % matlab SMT compatibiliy for arguments
+%! % matlab SMT compatibility for arguments
 %! syms r x u w v
 %! Pi=sym('pi');
 %! assert(logical( fourier(exp(-x^2)) == sqrt(Pi)/exp(w^2/4) ))
diff --git a/inst/@sym/function_handle.m b/inst/@sym/function_handle.m
index 86c34e229..416d27df5 100644
--- a/inst/@sym/function_handle.m
+++ b/inst/@sym/function_handle.m
@@ -1,4 +1,5 @@
-%% Copyright (C) 2014-2019, 2023 Colin B. Macdonald
+%% SPDX-License-Identifier: AGPL-3.0-or-later
+%% Copyright (C) 2014-2019, 2023-2024 Colin B. Macdonald
 %%
 %% This file is part of OctSymPy.
 %%
@@ -217,7 +218,7 @@
 %! assert(t1 == 30 && t2 == 8)
 
 %!test
-%! % cell arrays specfies order, overriding symvar order
+%! % cell arrays specify order, overriding symvar order
 %! h = function_handle(x*y, 12/y, 'vars', {y x});
 %! [t1, t2] = h(3, 6);
 %! assert(t1 == 18 && t2 == 4)
@@ -226,7 +227,7 @@
 %! assert(t1 == 18 && t2 == 4)
 
 %!test
-%! % cell arrays specfies order, overriding symvar order
+%! % cell arrays specify order, overriding symvar order
 %! h = function_handle(x*y, 12/y, 'vars', {y x});
 %! [t1, t2] = h(3, 6);
 %! assert(t1 == 18 && t2 == 4)
diff --git a/inst/@sym/horzcat.m b/inst/@sym/horzcat.m
index cac1fbd65..8af7c13ef 100644
--- a/inst/@sym/horzcat.m
+++ b/inst/@sym/horzcat.m
@@ -1,4 +1,5 @@
-%% Copyright (C) 2014-2017, 2019 Colin B. Macdonald
+%% SPDX-License-Identifier: AGPL-3.0-or-later
+%% Copyright (C) 2014-2017, 2019, 2024 Colin B. Macdonald
 %%
 %% This file is part of OctSymPy.
 %%
@@ -21,7 +22,7 @@
 %% @defop  Method   @@sym {horzcat} {(@var{x}, @var{y}, @dots{})}
 %% @defopx Operator @@sym {[@var{x}, @var{y}, @dots{}]} {}
 %% @defopx Operator @@sym {[@var{x} @var{y} @dots{}]} {}
-%% Horizontally concatentate symbolic arrays.
+%% Horizontally concatenate symbolic arrays.
 %%
 %% Example:
 %% @example
@@ -42,11 +43,10 @@
 %% @seealso{@@sym/vertcat, @@sym/cat}
 %% @end defop
 
-
 function h = horzcat(varargin)
 
   % special case for 0x0 but other empties should be checked for
-  % compatibilty
+  % compatibility
   cmd = {
           '_proc = []'
           'for i in _ins:'
diff --git a/inst/@sym/ifourier.m b/inst/@sym/ifourier.m
index 6efb26757..0b48c5657 100644
--- a/inst/@sym/ifourier.m
+++ b/inst/@sym/ifourier.m
@@ -1,4 +1,5 @@
-%% Copyright (C) 2014-2016, 2018-2019, 2022 Colin B. Macdonald
+%% SPDX-License-Identifier: AGPL-3.0-or-later
+%% Copyright (C) 2014-2016, 2018-2019, 2022, 2024 Colin B. Macdonald
 %% Copyright (C) 2015-2016 Andrés Prieto
 %% Copyright (C) 2015 Alexander Misel
 %%
@@ -86,7 +87,7 @@
   if (nargin == 3)
     k = sym(varargin{2});
   else
-    %% frequency domain variable not specifed
+    %% frequency domain variable not specified
     % if exactly one symbol has char(k) == 'k'...
     symbols = findsymbols (F);
     charsyms = cell (size (symbols));
diff --git a/inst/@sym/ilaplace.m b/inst/@sym/ilaplace.m
index 2be0ca284..8bc68a034 100644
--- a/inst/@sym/ilaplace.m
+++ b/inst/@sym/ilaplace.m
@@ -1,3 +1,4 @@
+%% SPDX-License-Identifier: AGPL-3.0-or-later
 %% Copyright (C) 2014-2016 Andrés Prieto
 %% Copyright (C) 2015-2016, 2018-2019, 2022-2024 Colin Macdonald
 %%
@@ -63,9 +64,9 @@
 %% @end group
 %% @end example
 %%
-%% By default the ouput is a function of @code{t} (or @code{x} if the
+%% By default the output is a function of @code{t} (or @code{x} if the
 %% inverse transform happens to be with respect to @code{t}).  This can
-%% be overriden by specifying @var{t}.  For example:
+%% be overridden by specifying @var{t}.  For example:
 %% @example
 %% @group
 %% syms s
diff --git a/inst/@sym/laplace.m b/inst/@sym/laplace.m
index 26c9efc1d..982fe3733 100644
--- a/inst/@sym/laplace.m
+++ b/inst/@sym/laplace.m
@@ -1,3 +1,4 @@
+%% SPDX-License-Identifier: AGPL-3.0-or-later
 %% Copyright (C) 2014-2016 Andrés Prieto
 %% Copyright (C) 2015-2016, 2019, 2024 Colin Macdonald
 %%
@@ -55,8 +56,8 @@
 %% @end group
 %% @end example
 %%
-%% By default the ouput is a function of @code{s} (or @code{z} if the Laplace
-%% transform happens to be with respect to @code{s}).  This can be overriden
+%% By default the output is a function of @code{s} (or @code{z} if the Laplace
+%% transform happens to be with respect to @code{s}).  This can be overridden
 %% by specifying @var{s}.  For example:
 %% @example
 %% @group
@@ -81,7 +82,7 @@
 %%
 %% If not specified by @var{t}, the independent variable is chosen by
 %% looking for a symbol named @code{t}.  If no such symbol is found,
-%% @pxref{@@sym/symvar} is used, which choses a variable close to @code{x}:
+%% @pxref{@@sym/symvar} is used, which chooses a variable close to @code{x}:
 %% @example
 %% @group
 %% syms a y
diff --git a/inst/@sym/private/mat_rclist_asgn.m b/inst/@sym/private/mat_rclist_asgn.m
index ce779776e..7df96f69d 100644
--- a/inst/@sym/private/mat_rclist_asgn.m
+++ b/inst/@sym/private/mat_rclist_asgn.m
@@ -1,4 +1,5 @@
-%% Copyright (C) 2014, 2016-2017, 2019, 2022 Colin B. Macdonald
+%% SPDX-License-Identifier: AGPL-3.0-or-later
+%% Copyright (C) 2014, 2016-2017, 2019, 2022, 2024 Colin B. Macdonald
 %% Copyright (C) 2020 Mike Miller
 %% Copyright (C) 2020 Fernando Alvarruiz
 %%
@@ -20,7 +21,7 @@
 
 %% -*- texinfo -*-
 %% @defun mat_rclist_asgn (@var{A}, @var{r}, @var{c}, @var{B})
-%% Private helper routine for sym array assigment using lists.
+%% Private helper routine for sym array assignment using lists.
 %%
 %% @code{(R(i),C(i))} specify entries of the matrix @var{A}.
 %% We execute @code{A(R(i),C(i)) = B(i)}.
diff --git a/inst/@sym/subs.m b/inst/@sym/subs.m
index 543344090..1cdbe8ee0 100644
--- a/inst/@sym/subs.m
+++ b/inst/@sym/subs.m
@@ -1,4 +1,5 @@
-%% Copyright (C) 2014-2017, 2019, 2022 Colin B. Macdonald
+%% SPDX-License-Identifier: AGPL-3.0-or-later
+%% Copyright (C) 2014-2017, 2019, 2022, 2024 Colin B. Macdonald
 %%
 %% This file is part of OctSymPy.
 %%
@@ -123,7 +124,7 @@
 %% @end group
 %% @end example
 %%
-%% When using multiple variables and matrix substitions, it may be
+%% When using multiple variables and matrix substutions, it may be
 %% helpful to use cell arrays:
 %% @example
 %% @group
@@ -170,7 +171,6 @@
 %% @seealso{@@sym/symfun}
 %% @end defmethod
 
-
 function g = subs(f, in, out)
 
   if (nargin > 3)
@@ -255,7 +255,7 @@
     '# more complicated when dealing with matrix/vector'
     'sizes = {(a.shape if a.is_Matrix else (1, 1)) for a in yy}'
     'sizes.discard((1, 1))'
-    'assert len(sizes) == 1, "all substitions must be same size or scalar"'
+    'assert len(sizes) == 1, "all substitutions must be same size or scalar"'
     'size = sizes.pop()'
     'numel = prod(size)'
     'g = [0]*numel'
diff --git a/inst/@sym/sym.m b/inst/@sym/sym.m
index 7d490af0d..56eef76c4 100644
--- a/inst/@sym/sym.m
+++ b/inst/@sym/sym.m
@@ -1,3 +1,4 @@
+%% SPDX-License-Identifier: AGPL-3.0-or-later
 %% Copyright (C) 2014-2019, 2022-2024 Colin B. Macdonald
 %% Copyright (C) 2016 Lagu
 %%
@@ -1087,9 +1088,9 @@
 %! assert (strcmp (s1, s2))
 
 %!test
-%! % For SMT 2014 compatibilty, I and E would become ImaginaryUnit and Exp(1)
+%! % For SMT 2014 compatibility, I and E would become ImaginaryUnit and Exp(1)
 %! % but I'm not sure this is by design.  This test would need to change if
-%! % we want stricter SMT compatibilty.
+%! % we want stricter SMT compatibility.
 %! f = sym ('f(x, I, E)');
 %! s1 = sympy (f);
 %! s2 = 'Function(''f'')(Symbol(''x''), Symbol(''I''), Symbol(''E''))';
diff --git a/inst/@sym/vertcat.m b/inst/@sym/vertcat.m
index 09a8ea787..9f46f6dab 100644
--- a/inst/@sym/vertcat.m
+++ b/inst/@sym/vertcat.m
@@ -1,4 +1,5 @@
-%% Copyright (C) 2014-2017, 2019 Colin B. Macdonald
+%% SPDX-License-Identifier: AGPL-3.0-or-later
+%% Copyright (C) 2014-2017, 2019, 2024 Colin B. Macdonald
 %%
 %% This file is part of OctSymPy.
 %%
@@ -20,7 +21,7 @@
 %% @documentencoding UTF-8
 %% @defop  Method   @@sym {vertcat} {(@var{x}, @var{y}, @dots{})}
 %% @defopx Operator @@sym {[@var{x}; @var{y}; @dots{}]} {}
-%% Vertically concatentate symbolic arrays.
+%% Vertically concatenate symbolic arrays.
 %%
 %% Example:
 %% @example
@@ -39,11 +40,10 @@
 %% @seealso{@@sym/horzcat, @@sym/cat}
 %% @end defop
 
-
 function h = vertcat(varargin)
 
   % special case for 0x0 but other empties should be checked for
-  % compatibilty
+  % compatibility
   cmd = {
           '_proc = []'
           'for i in _ins:'
diff --git a/inst/@symfun/int.m b/inst/@symfun/int.m
index 149a09616..5ef6bc050 100644
--- a/inst/@symfun/int.m
+++ b/inst/@symfun/int.m
@@ -1,4 +1,5 @@
-%% Copyright (C) 2014, 2016, 2019 Colin B. Macdonald
+%% SPDX-License-Identifier: AGPL-3.0-or-later
+%% Copyright (C) 2014, 2016, 2019, 2024 Colin B. Macdonald
 %%
 %% This file is part of OctSymPy.
 %%
@@ -50,9 +51,6 @@
 %% @seealso{@@sym/int, @@symfun/diff}
 %% @end defmethod
 
-%% Author: Colin B. Macdonald
-%% Keywords: symbolic, integration
-
 function F = int(f, varargin)
 
   if (nargin == 1)
@@ -106,7 +104,7 @@
 %! assert (~isa(g, 'symfun'))
 
 %!test
-%! % ... even if the input is abstract funcion
+%! % ... even if the input is abstract function
 %! syms f(x)
 %! g = int(f, x, 0, 2);
 %! assert (isa(g, 'sym'))
diff --git a/inst/findsymbols.m b/inst/findsymbols.m
index 9d43dd09b..4d260ee60 100644
--- a/inst/findsymbols.m
+++ b/inst/findsymbols.m
@@ -1,4 +1,5 @@
-%% Copyright (C) 2014, 2016, 2018-2019, 2022 Colin B. Macdonald
+%% SPDX-License-Identifier: AGPL-3.0-or-later
+%% Copyright (C) 2014, 2016, 2018-2019, 2022, 2024 Colin B. Macdonald
 %%
 %% This file is part of OctSymPy.
 %%
@@ -163,7 +164,7 @@
 %! assert (isequal (findsymbols(f), {a y}))
 
 %!test
-%! % sorts lexigraphically, same as symvar *with single input*
+%! % sorts lexicographically, same as symvar *with single input*
 %! % (note symvar does something different with 2 inputs).
 %! syms A B a b x y X Y
 %! f = A*a*B*b*y*X*Y*x;
diff --git a/inst/poly2sym.m b/inst/poly2sym.m
index 461400f8d..b28d336cb 100644
--- a/inst/poly2sym.m
+++ b/inst/poly2sym.m
@@ -1,5 +1,6 @@
+%% SPDX-License-Identifier: AGPL-3.0-or-later
 %% Copyright (C) 2003 Willem J. Atsma
-%% Copyright (C) 2014-2016 Colin B. Macdonald
+%% Copyright (C) 2014-2016, 2024 Colin B. Macdonald
 %%
 %% This program is free software; you can redistribute it and/or
 %% modify it under the terms of the GNU General Public
@@ -88,7 +89,7 @@
 %!assert(isAlways(  poly2sym([1 2 3 4],5) == subs(p,x,5) ))
 %!assert(isequal(  poly2sym ([1]),  1  ))
 %!assert(isequal(  poly2sym ([]),  0  ))
-%% symbolic coefficents
+%% symbolic coefficients
 %!assert(isAlways(  poly2sym(sym([1 2 3 4]),x) == p  ))
 %!assert(isAlways(  poly2sym([a b c],x) == a*x^2 + b*x + c  ))
 %!assert(isAlways(  poly2sym([a b c]) == a*x^2 + b*x + c  ))
diff --git a/inst/private/python_ipc_popen2.m b/inst/private/python_ipc_popen2.m
index 2d82de5e9..75b0e0ffa 100644
--- a/inst/private/python_ipc_popen2.m
+++ b/inst/private/python_ipc_popen2.m
@@ -1,4 +1,5 @@
-%% Copyright (C) 2014-2019, 2022 Colin B. Macdonald
+%% SPDX-License-Identifier: AGPL-3.0-or-later
+%% Copyright (C) 2014-2019, 2022, 2024 Colin B. Macdonald
 %% Copyright (C) 2018, 2020 Mike Miller
 %% Copyright (C) 2022 Alex Vong
 %%
@@ -33,6 +34,7 @@
 %% @code{@var{info}.raw}: the raw output, for debugging.
 %% @end deftypefun
 
+
 function [A, info] = python_ipc_popen2(what, cmd, varargin)
 
   persistent emergency_cleanup fin fout pid
@@ -138,7 +140,7 @@
 
   %% load all the inputs into python as pickles
   % they will be in the list '_ins'
-  % there is a try-except block here, sends a block if sucessful
+  % there is a try-except block here, sends a block if successful
   loc = python_copy_vars_to('_ins', true, varargin{:});
   write_lines(fin, loc, true);
   fflush(fin);
diff --git a/inst/vpa.m b/inst/vpa.m
index 9ad5389e8..59320030e 100644
--- a/inst/vpa.m
+++ b/inst/vpa.m
@@ -1,4 +1,5 @@
-%% Copyright (C) 2014-2019, 2021-2022 Colin B. Macdonald
+%% SPDX-License-Identifier: AGPL-3.0-or-later
+%% Copyright (C) 2014-2019, 2021-2022, 2024 Colin B. Macdonald
 %%
 %% This file is part of OctSymPy.
 %%
@@ -84,7 +85,7 @@
 %% @end group
 %% @end example
 %%
-%% Instead, it is preferrable to use @code{sym} or @code{vpa} on the
+%% Instead, it is preferable to use @code{sym} or @code{vpa} on the
 %% inner-most parts of your expression:
 %% @example
 %% @group