This is still experimental.
diff -x '*.orig' -x '*.swp' -x '*.rej' -Naur 10.9-0/FreeFileSync/Source/ui/folder_selector.cpp 10.9-1/FreeFileSync/Source/ui/folder_selector.cpp
--- 10.9-0/FreeFileSync/Source/ui/folder_selector.cpp   2019-02-10 16:42:28.960039117 -0500
+++ 10.9-1/FreeFileSync/Source/ui/folder_selector.cpp   2019-02-10 20:20:11.981339625 -0500
@@ -231,7 +231,7 @@

     std::optional<std::wstring> parallelOpsDisabledReason;

-        parallelOpsDisabledReason = _("Requires FreeFileSync Donation Edition");
+    //  parallelOpsDisabledReason = _("Requires FreeFileSync Donation Edition");

     if (showCloudSetupDialog(parent_, folderPathPhrase, parallelOps, get(parallelOpsDisabledReason)) != ReturnSmallDlg::BUTTON_OKAY)
         return;
diff -Naur -x '*.orig' -x '*.rej' 10.9-0/FreeFileSync/Source/ui/sync_cfg.cpp 10.9-1/FreeFileSync/Source/ui/sync_cfg.cpp
--- 10.21-0/FreeFileSync/Source/ui/sync_cfg.cpp 2020-03-18 08:56:08.644066742 -0400
+++ 10.21-1/FreeFileSync/Source/ui/sync_cfg.cpp 2020-03-18 09:13:30.459409986 -0400
@@ -290,7 +290,7 @@
 commandHistoryOut_(commandHistory),
 globalPairCfg_(globalPairCfg),
 localPairCfg_(localPairConfig),
-    enableExtraFeatures_(false),
+    enableExtraFeatures_(true),
 showMultipleCfgs_(showMultipleCfgs)
 {
     setStandardButtonLayout(*bSizerStdButtons, StdButtons().setAffirmative(m_buttonOkay).setCancel(m_buttonCancel));