diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 681900036811d1fa7690c0b936a061c06e5083a7..e8b289b43b673b467caeea727f9f520b2947c3c9 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -10,9 +10,9 @@ test_matlab:
   script:
     - make check-matlab
 
-test_octave:
+test_old_matlab:
   stage: test
   variables:
-    OPENBLAS_NUM_THREADS: 1
+    MATLAB: /usr/local/MATLAB/R2015a/bin/matlab
   script:
-    - make check-octave
\ No newline at end of file
+    - make check-matlab
\ No newline at end of file
diff --git a/Makefile b/Makefile
index efd1de9a3d71cdd65595da32e7d99b3707e23b7f..99147cc4d3c9e1f729582db1117eb748e17bfc1e 100644
--- a/Makefile
+++ b/Makefile
@@ -1,13 +1,10 @@
-OCTAVE ?= octave-cli
 MATLAB ?= $(shell which matlab)
 
+all: check-matlab
+
 m-unit-tests/src/mtest.m:
 	git clone https://git.dynare.org/Dynare/m-unit-tests
 
-check-octave: m-unit-tests/src/mtest.m
-	@cd tests ;\
-	$(OCTAVE) --no-init-file --silent --no-history --eval "addpath([pwd() '/../m-unit-tests/src']); runalltests" && [ ! -f ./failed ] && [ -f ./pass ]
-
 check-matlab: m-unit-tests/src/mtest.m
 	@$(MATLAB)  -nosplash -nodisplay -r "addpath([pwd '/m-unit-tests/src']); cd tests; runalltests; quit" && [ ! -f ./tests/failed ] && [ -f ./tests/pass ]
 
diff --git a/src/initialize_mdbnomics.m b/src/initialize_mdbnomics.m
index 7db683f7a1bdee43600625a511e17c2c154013b9..3665002858838660e0ce1bc066c706ab9aadc3f5 100644
--- a/src/initialize_mdbnomics.m
+++ b/src/initialize_mdbnomics.m
@@ -50,8 +50,8 @@ P = cellfun(@(c)[mdbnomics_src_root c], p, 'uni', false);
 addpath(P{:});
 
 % Check minimal MATLAB and Octave requirements.
-if (isoctave && octave_ver_less_than('6')) || matlab_ver_less_than('8.5')
-    error('The minimum MATLAB requirement of this package is R2015a, and the minimum Octave requirement of this package is version 6.');
+if matlab_ver_less_than('8.5')
+    error('The minimum MATLAB requirement of this package is R2015a.');
 end
 
 assignin('caller', 'mdbnomics_src_root', mdbnomics_src_root);
diff --git a/src/utils/iter_filtered_series.m b/src/utils/iter_filtered_series.m
index 51e9149d616b4c5a3d24a83c2d392c10ede00de1..b22d0506f12af0531fc1cb532d96ca548f21d651 100644
--- a/src/utils/iter_filtered_series.m
+++ b/src/utils/iter_filtered_series.m
@@ -58,7 +58,6 @@ for gg = 1:size(grouped_series, 2)
         posted_series_list = jsonencode(posted_series_list);
     end
     
-    posted_series_list = transform_json_request(posted_series_list);
     json_request = sprintf('{"filters":%s,"series":%s}', dbnomics_filters, posted_series_list);
  
     try