diff --git a/requirements/edx/base.txt b/requirements/edx/base.txt
index a7fbc4aa3d54..20c7078370a8 100644
--- a/requirements/edx/base.txt
+++ b/requirements/edx/base.txt
@@ -1319,8 +1319,9 @@ xblock-utils==4.0.0
     # via
     #   edx-sga
     #   xblock-poll
-xblocks-contrib==0.17.0
+xblocks-contrib @ git+https://github.com/irfanuddinahmad/xblocks-core.git@irfanuddinahmad/modernize-problem-block-js-438
     # via -r requirements/edx/bundled.in
+    # sandbox: testing PR #262 (modernize Problem Block JS to ES6+)
 xmlsec==1.3.14
     # via
     #   -c requirements/constraints.txt
diff --git a/requirements/edx/development.txt b/requirements/edx/development.txt
index edf3a2623a6c..e572ad8b8582 100644
--- a/requirements/edx/development.txt
+++ b/requirements/edx/development.txt
@@ -2330,10 +2330,11 @@ xblock-utils==4.0.0
     #   -r requirements/edx/testing.txt
     #   edx-sga
     #   xblock-poll
-xblocks-contrib==0.17.0
+xblocks-contrib @ git+https://github.com/irfanuddinahmad/xblocks-core.git@irfanuddinahmad/modernize-problem-block-js-438
     # via
     #   -r requirements/edx/doc.txt
     #   -r requirements/edx/testing.txt
+    # sandbox: testing PR #262 (modernize Problem Block JS to ES6+)
 xmlsec==1.3.14
     # via
     #   -c requirements/constraints.txt
diff --git a/requirements/edx/doc.txt b/requirements/edx/doc.txt
index 7777d301f931..a3ee2ac88748 100644
--- a/requirements/edx/doc.txt
+++ b/requirements/edx/doc.txt
@@ -1659,8 +1659,9 @@ xblock-utils==4.0.0
     #   -r requirements/edx/base.txt
     #   edx-sga
     #   xblock-poll
-xblocks-contrib==0.17.0
+xblocks-contrib @ git+https://github.com/irfanuddinahmad/xblocks-core.git@irfanuddinahmad/modernize-problem-block-js-438
     # via -r requirements/edx/base.txt
+    # sandbox: testing PR #262 (modernize Problem Block JS to ES6+)
 xmlsec==1.3.14
     # via
     #   -c requirements/constraints.txt
diff --git a/requirements/edx/testing.txt b/requirements/edx/testing.txt
index 6743c9ac2b45..d4000bd7865e 100644
--- a/requirements/edx/testing.txt
+++ b/requirements/edx/testing.txt
@@ -1740,8 +1740,9 @@ xblock-utils==4.0.0
     #   -r requirements/edx/base.txt
     #   edx-sga
     #   xblock-poll
-xblocks-contrib==0.17.0
+xblocks-contrib @ git+https://github.com/irfanuddinahmad/xblocks-core.git@irfanuddinahmad/modernize-problem-block-js-438
     # via -r requirements/edx/base.txt
+    # sandbox: testing PR #262 (modernize Problem Block JS to ES6+)
 xmlsec==1.3.14
     # via
     #   -c requirements/constraints.txt