diff --git a/lib/commands/install.js b/lib/commands/install.js
index 309fb4e98..4246be427 100644
--- a/lib/commands/install.js
+++ b/lib/commands/install.js
@@ -139,8 +139,8 @@ class InstallCommand extends Command {
         if (semver.gte(version, '5.63.0')) {
             // Create a symlink to the theme from the current version
             return symlinkSync(
-                path.join(process.cwd(), 'current', 'content', 'themes', 'masthead'),
-                path.join(process.cwd(), 'content', 'themes', 'masthead')
+                path.join(process.cwd(), 'current', 'content', 'themes', 'source'),
+                path.join(process.cwd(), 'content', 'themes', 'source')
             );
         } else {
             return symlinkSync(
diff --git a/lib/commands/update.js b/lib/commands/update.js
index 188ed2737..27802c153 100644
--- a/lib/commands/update.js
+++ b/lib/commands/update.js
@@ -224,11 +224,11 @@ class UpdateCommand extends Command {
         fs.removeSync(path.join(process.cwd(), 'current'));
         symlinkSync(installPath, path.join(process.cwd(), 'current'));
 
-        // If upgrading from a version < 5.63.0, we need to symlink masthead so it is installed and available to update
+        // If upgrading from a version < 5.63.0, we need to symlink source so it is installed and available to update
         if (semver.lt(instance.version, '5.63.0') && semver.gte(version, '5.63.0')) {
             symlinkSync(
-                path.join(process.cwd(), 'current', 'content', 'themes', 'masthead'),
-                path.join(process.cwd(), 'content', 'themes', 'masthead')
+                path.join(process.cwd(), 'current', 'content', 'themes', 'source'),
+                path.join(process.cwd(), 'content', 'themes', 'source')
             );
         }
 
diff --git a/lib/tasks/backup.js b/lib/tasks/backup.js
index a380a24eb..8d8a692db 100644
--- a/lib/tasks/backup.js
+++ b/lib/tasks/backup.js
@@ -74,7 +74,7 @@ module.exports = async function (ui, instance) {
     const zipPath = path.join(process.cwd(), `backup-${backupSuffix}.zip`);
 
     try {
-        await zip.compress(path.join(instance.dir, 'content/'), zipPath, {glob: `{data/${contentExportFile},data/${membersExportFile},files/**,images/**,media/**,settings/**,themes/**}`, ignore: 'themes/casper,themes/masthead'});
+        await zip.compress(path.join(instance.dir, 'content/'), zipPath, {glob: `{data/${contentExportFile},data/${membersExportFile},files/**,images/**,media/**,settings/**,themes/**}`, ignore: 'themes/casper,themes/source'});
     } catch (err) {
         throw new ProcessError(err);
     }
diff --git a/test/unit/commands/install-spec.js b/test/unit/commands/install-spec.js
index 81d9a1a05..785e118dc 100644
--- a/test/unit/commands/install-spec.js
+++ b/test/unit/commands/install-spec.js
@@ -413,7 +413,7 @@ describe('Unit: Commands > Install', function () {
     });
 
     describe('tasks > defaultTheme', function () {
-        it('links masthead version correctly if version >= 5.63.0', function () {
+        it('links source version correctly if version >= 5.63.0', function () {
             const symlinkSyncStub = sinon.stub();
             const InstallCommand = proxyquire(modulePath, {
                 'symlink-or-copy': {sync: symlinkSyncStub}
@@ -425,8 +425,8 @@ describe('Unit: Commands > Install', function () {
             testInstance.defaultTheme(context);
             expect(symlinkSyncStub.calledOnce).to.be.true;
             expect(symlinkSyncStub.calledWithExactly(
-                path.join(process.cwd(), 'current/content/themes/masthead'),
-                path.join(process.cwd(), 'content/themes/masthead')
+                path.join(process.cwd(), 'current/content/themes/source'),
+                path.join(process.cwd(), 'content/themes/source')
             ));
         });
 
diff --git a/test/unit/commands/update-spec.js b/test/unit/commands/update-spec.js
index df847b40b..d35c3e382 100644
--- a/test/unit/commands/update-spec.js
+++ b/test/unit/commands/update-spec.js
@@ -1069,10 +1069,10 @@ describe('Unit: Commands > Update', function () {
             expect(instance.nodeVersion).to.equal(process.versions.node);
         });
 
-        it('installs masthead theme when upgrading from < 5.63.0 to >= 5.63.0', function () {
+        it('installs source theme when upgrading from < 5.63.0 to >= 5.63.0', function () {
             const command = new UpdateCommand({}, {});
             const envCfg = {
-                dirs: ['versions/5.62.0', 'versions/5.63.0', 'versions/5.63.0/content/themes/masthead', 'content/themes'],
+                dirs: ['versions/5.62.0', 'versions/5.63.0', 'versions/5.63.0/content/themes/source', 'content/themes'],
                 links: [['versions/5.62.0', 'current']]
             };
             const env = setupTestFolder(envCfg);