diff --git a/src/consensus/activation.cpp b/src/consensus/activation.cpp
--- a/src/consensus/activation.cpp
+++ b/src/consensus/activation.cpp
@@ -68,8 +68,7 @@
         return false;
     }
 
-    return pindexPrev->GetMedianTimePast() >=
-           gArgs.GetArg("-phononactivationtime", params.phononActivationTime);
+    return pindexPrev->GetMedianTimePast() >= params.phononActivationTime;
 }
 
 bool IsAxionEnabled(const Consensus::Params &params,
diff --git a/src/init.cpp b/src/init.cpp
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -362,8 +362,6 @@
         "-allowselfsignedrootcertificates", "-choosedatadir", "-lang=<lang>",
         "-min", "-resetguisettings", "-rootcertificates=<file>", "-splash",
         "-uiplatform",
-        // TODO remove after the May 2020 upgrade
-        "-phononactivationtime",
         // TODO remove after the November 2020 upgrade
         "-axionactivationtime"};
 
diff --git a/src/test/activation_tests.cpp b/src/test/activation_tests.cpp
--- a/src/test/activation_tests.cpp
+++ b/src/test/activation_tests.cpp
@@ -42,11 +42,8 @@
 }
 
 BOOST_AUTO_TEST_CASE(isphononenabled) {
-    CBlockIndex prev;
-
     const Consensus::Params &params = Params().GetConsensus();
-    const auto activation =
-        gArgs.GetArg("-phononactivationtime", params.phononActivationTime);
+    const auto activation = params.phononActivationTime;
     SetMockTime(activation - 1000000);
 
     BOOST_CHECK(!IsPhononEnabled(params, nullptr));
@@ -68,8 +65,6 @@
 }
 
 BOOST_AUTO_TEST_CASE(isaxionenabled) {
-    CBlockIndex prev;
-
     const Consensus::Params &params = Params().GetConsensus();
     const auto activation =
         gArgs.GetArg("-axionactivationtime", params.axionActivationTime);
diff --git a/src/test/main.cpp b/src/test/main.cpp
--- a/src/test/main.cpp
+++ b/src/test/main.cpp
@@ -22,7 +22,6 @@
 
         const std::set<std::string> testArgs = {
             testsuitename,
-            "-phononactivationtime",
             "-axionactivationtime",
         };
 
diff --git a/test/lint/check-doc.py b/test/lint/check-doc.py
--- a/test/lint/check-doc.py
+++ b/test/lint/check-doc.py
@@ -46,8 +46,6 @@
                                        '-forcecompactdb',
                                        '-parkdeepreorg',
                                        '-automaticunparking',
-                                       # Remove after May 2020 upgrade
-                                       '-phononactivationtime',
                                        # Remove after November 2020 upgrade
                                        '-axionactivationtime',
                                        '-replayprotectionactivationtime',