diff --git a/matlab/dsge_likelihood.m b/matlab/dsge_likelihood.m
index 62d5ff570..8ff23126c 100644
--- a/matlab/dsge_likelihood.m
+++ b/matlab/dsge_likelihood.m
@@ -115,7 +115,7 @@ function [fval,info,exit_flag,DLIK,Hess,SteadyState,trend_coeff,Model,DynareOpti
 %! @end deftypefn
 %@eod:
 
-% Copyright (C) 2004-2020 Dynare Team
+% Copyright (C) 2004-2021 Dynare Team
 %
 % This file is part of Dynare.
 %
@@ -148,7 +148,12 @@ end
 Hess        = [];
 
 % Ensure that xparam1 is a column vector.
-xparam1 = xparam1(:);
+% (Don't do the transformation if xparam1 is empty, otherwise it would become a
+%  0×1 matrix, which create issues with older MATLABs when comparing with [] in
+%  check_bounds_and_definiteness_estimation)
+if ~isempty(xparam1)
+    xparam1 = xparam1(:);
+end
 
 if DynareOptions.estimation_dll
     [fval,exit_flag,SteadyState,trend_coeff,info,params,H,Q] ...
diff --git a/matlab/dsge_var_likelihood.m b/matlab/dsge_var_likelihood.m
index 596136ce8..c1b490819 100644
--- a/matlab/dsge_var_likelihood.m
+++ b/matlab/dsge_var_likelihood.m
@@ -37,7 +37,7 @@ function [fval,info,exit_flag,grad,hess,SteadyState,trend_coeff,PHI_tilde,SIGMA_
 % SPECIAL REQUIREMENTS
 %   None.
 
-% Copyright (C) 2006-2018 Dynare Team
+% Copyright (C) 2006-2021 Dynare Team
 %
 % This file is part of Dynare.
 %
@@ -69,7 +69,12 @@ prior = [];
 trend_coeff=[];
 
 % Ensure that xparam1 is a column vector.
-xparam1 = xparam1(:);
+% (Don't do the transformation if xparam1 is empty, otherwise it would become a
+%  0×1 matrix, which create issues with older MATLABs when comparing with [] in
+%  check_bounds_and_definiteness_estimation)
+if ~isempty(xparam1)
+    xparam1 = xparam1(:);
+end
 
 % Initialization of of the index for parameter dsge_prior_weight in Model.params.
 if isempty(dsge_prior_weight_idx)
@@ -317,4 +322,4 @@ if (nargout==11)
     prior.ArtificialSampleSize = fix(dsge_prior_weight*NumberOfObservations);
     prior.DF = prior.ArtificialSampleSize - NumberOfParameters - NumberOfObservedVariables;
     prior.iGXX_star = iGXX;
-end
\ No newline at end of file
+end
diff --git a/matlab/non_linear_dsge_likelihood.m b/matlab/non_linear_dsge_likelihood.m
index b5a9ff76f..7f34ab2d3 100644
--- a/matlab/non_linear_dsge_likelihood.m
+++ b/matlab/non_linear_dsge_likelihood.m
@@ -26,7 +26,7 @@ function [fval,info,exit_flag,DLIK,Hess,ys,trend_coeff,Model,DynareOptions,Bayes
 % - BayesInfo               [struct]              See INPUTS section.
 % - DynareResults           [struct]              Updated DynareResults structure described in INPUTS section.
 
-% Copyright (C) 2010-2019 Dynare Team
+% Copyright (C) 2010-2021 Dynare Team
 %
 % This file is part of Dynare.
 %
@@ -52,7 +52,12 @@ DLIK            = [];
 Hess            = [];
 
 % Ensure that xparam1 is a column vector.
-xparam1 = xparam1(:);
+% (Don't do the transformation if xparam1 is empty, otherwise it would become a
+%  0×1 matrix, which create issues with older MATLABs when comparing with [] in
+%  check_bounds_and_definiteness_estimation)
+if ~isempty(xparam1)
+    xparam1 = xparam1(:);
+end
 
 % Issue an error if loglinear option is used.
 if DynareOptions.loglinear