diff --git a/server/extension/Makefile b/server/extension/Makefile
index 968e51c..f160612 100644
--- a/server/extension/Makefile
+++ b/server/extension/Makefile
@@ -1,11 +1,10 @@
 # Makefile to generate the extension out of separate sql source files.
 # Once a version is released, it is not meant to be changed. E.g: once version 0.0.1 is out, it SHALL NOT be changed.
 EXTENSION = cdb_dataservices_server
-EXTVERSION = $(shell grep default_version $(EXTENSION).control | sed -e "s/default_version[[:space:]]*=[[:space:]]*'\([^']*\)'/\1/")
+EXTVERSION = $(shell grep default_version $(EXTENSION).control.in | sed -e "s/default_version[[:space:]]*=[[:space:]]*'\([^']*\)'/\1/")
 # The new version to be generated from templates
 SED = sed
 ERB = erb
-REPLACEMENTS = -i 's/$(EXTVERSION)/$(NEW_VERSION)/g'
 NEW_EXTENSION_ARTIFACT = $(EXTENSION)--$(EXTVERSION).sql
 AWK = awk
 
@@ -14,7 +13,8 @@ PG_CONFIG         = pg_config
 PG_PARALLEL      := $(shell $(PG_CONFIG) --version | ($(AWK) '{$$2*=1000; if ($$2 >= 9600) print 1; else print 0;}' 2> /dev/null || echo 0))
 
 REGRESS = $(notdir $(basename $(sort $(wildcard test/sql/*test.sql))))
-TEST_DIR = test/
+REGRESS_EXPEC = $(notdir $(basename $(sort $(wildcard test/expected/*test.out))))
+TEST_DIR = test_out
 REGRESS_OPTS = --inputdir='$(TEST_DIR)' --outputdir='$(TEST_DIR)' --user='postgres'
 
 # DATA is a special variable used by postgres build infrastructure
@@ -27,15 +27,29 @@ DATA = $(NEW_EXTENSION_ARTIFACT) \
 		 $(OLD_VERSIONS)
 SOURCES_DATA_DIR = sql/
 SOURCES_DATA = $(wildcard sql/*.sql)
+SOURCES_DATA_DIR_OUT = sql_out/
 
 # postgres build stuff
 PG_CONFIG = pg_config
 PGXS := $(shell $(PG_CONFIG) --pgxs)
 include $(PGXS)
 
+# PG12 compatibility
+PG_VERSION := $(shell $(PG_CONFIG) --version | $(AWK) '{split($$2,a,"."); print a[1]}')
+PG_12_GE := $(shell [ $(PG_VERSION) -ge 12 ] && echo true)
+PLPYTHONU := plpythonu
+ifeq ($(PG_12_GE), true)
+PLPYTHONU := plpython3u
+endif
+
+REPLACEMENTS = -e 's/@@plpythonu@@/$(PLPYTHONU)/g'
+ifneq ($(NEW_VERSION),)
+REPLACEMENTS += -e 's/$(EXTVERSION)/$(NEW_VERSION)/g'
+endif
+
 $(NEW_EXTENSION_ARTIFACT): $(SOURCES_DATA)
 	rm -f $@
-	cat $(SOURCES_DATA_DIR)/*.sql >> $@
+	cat $(SOURCES_DATA_DIR_OUT)/*.sql >> $@
 ifeq ($(PG_PARALLEL), 0)
 # Remove PARALLEL in aggregates and functions
 	$(eval TMPFILE := $(shell mktemp /tmp/$(basename $0).XXXXXXXX))
@@ -44,16 +58,19 @@ ifeq ($(PG_PARALLEL), 0)
 	mv $(TMPFILE) $@
 endif
 
+$(EXTENSION).control: $(EXTENSION).control.in Makefile
+	$(SED) $(REPLACEMENTS)  $< > $@
+
 .PHONY: all
-all: $(DATA)
+all: replace_variables $(DATA)
 
 .PHONY: release
-release: $(EXTENSION).control $(SOURCES_DATA)
+release: replace_variables $(EXTENSION).control $(SOURCES_DATA)
 	test -n "$(NEW_VERSION)"  # $$NEW_VERSION VARIABLE MISSING. Eg. make release NEW_VERSION=0.x.0
 	git mv *.sql old_versions
-	$(SED) $(REPLACEMENTS) $(EXTENSION).control
+	$(SED) $(REPLACEMENTS) $(EXTENSION).control.in > $(EXTENSION).control
 	git add $(EXTENSION).control
-	cat $(SOURCES_DATA_DIR)/*.sql > $(EXTENSION)--$(NEW_VERSION).sql
+	cat $(SOURCES_DATA_DIR_OUT)/*.sql > $(EXTENSION)--$(NEW_VERSION).sql
 	$(ERB) version=$(NEW_VERSION) upgrade_downgrade_template.erb > $(EXTENSION)--$(EXTVERSION)--$(NEW_VERSION).sql
 	$(ERB) version=$(EXTVERSION) upgrade_downgrade_template.erb > $(EXTENSION)--$(NEW_VERSION)--$(EXTVERSION).sql
 	git add $(EXTENSION)--$(NEW_VERSION).sql
@@ -66,6 +83,9 @@ release: $(EXTENSION).control $(SOURCES_DATA)
 .PHONY: devclean
 devclean:
 	rm -f $(NEW_EXTENSION_ARTIFACT)
+	rm -rf $(TEST_DIR)
+	rm -rf $(SOURCES_DATA_DIR_OUT)
+	rm -rf $(EXTENSION).control
 
 # If needed remove PARALLEL tags from the release files
 release_remove_parallel_deploy:
@@ -82,6 +102,30 @@ deploy: release_remove_parallel_deploy
 	$(INSTALL_DATA) $(EXTENSION).control '$(DESTDIR)$(datadir)/extension/'
 	$(INSTALL_DATA) old_versions/*.sql *.sql '$(DESTDIR)$(datadir)/extension/'
 
+# Replacing variables defined within test files
+replace_variables:
+	# tests
+	mkdir -p $(TEST_DIR)
+	mkdir -p $(TEST_DIR)/expected
+	mkdir -p $(TEST_DIR)/sql
+	for f in $(REGRESS); do \
+		cat test/sql/$${f}.sql | \
+		sed -e 's/@@plpythonu@@/$(PLPYTHONU)/g' \
+		> $(TEST_DIR)/sql/$${f}.sql; \
+	done
+	for f in $(REGRESS_EXPEC); do \
+		cat test/expected/$${f}.out | \
+		sed -e 's/@@plpythonu@@/$(PLPYTHONU)/g' \
+		> $(TEST_DIR)/expected/$${f}.out; \
+	done
+	# data
+	mkdir -p $(SOURCES_DATA_DIR_OUT)
+	for f in $(notdir $(SOURCES_DATA)); do \
+		cat $(SOURCES_DATA_DIR)/$${f} | \
+		sed -e 's/@@plpythonu@@/$(PLPYTHONU)/g' \
+		> $(SOURCES_DATA_DIR_OUT)/$${f}; \
+	done
+
 install: deploy
 
 reinstall: install
diff --git a/server/extension/cdb_dataservices_server.control b/server/extension/cdb_dataservices_server.control.in
similarity index 85%
rename from server/extension/cdb_dataservices_server.control
rename to server/extension/cdb_dataservices_server.control.in
index 3e18400..c0d362e 100644
--- a/server/extension/cdb_dataservices_server.control
+++ b/server/extension/cdb_dataservices_server.control.in
@@ -1,5 +1,5 @@
 comment = 'CartoDB dataservices server extension'
-default_version = '0.37.0'
+default_version = '0.38.0'
 requires = '@@plpythonu@@, plproxy, postgis, cdb_geocoder'
 superuser = true
 schema = cdb_dataservices_server