diff --git a/src/cmd/cmd.cpp b/src/cmd/cmd.cpp
index 5b1de5e64..ac0a7051e 100644
--- a/src/cmd/cmd.cpp
+++ b/src/cmd/cmd.cpp
@@ -505,6 +505,11 @@ restart_sync:
         selectiveSyncFixup(&db, selectiveSyncList);
     }
 
+    SyncOptions opt;
+    opt.fillFromEnvironmentVariables();
+    opt.verifyChunkSizes();
+    opt._deltaSyncEnabled = false;
+    opt._deltaSyncMinFileSize = false;
     SyncEngine engine(account, options.source_dir, folder, &db);
     engine.setIgnoreHiddenFiles(options.ignoreHiddenFiles);
     engine.setNetworkLimits(options.uplimit, options.downlimit);
diff --git a/src/gui/folder.cpp b/src/gui/folder.cpp
index 4fb5a259e..814f83f82 100644
--- a/src/gui/folder.cpp
+++ b/src/gui/folder.cpp
@@ -874,42 +874,18 @@ void Folder::setSyncOptions()
     opt._confirmExternalStorage = cfgFile.confirmExternalStorage();
     opt._moveFilesToTrash = cfgFile.moveToTrash();
     opt._vfs = _vfs;
+    opt._parallelNetworkJobs = _accountState->account()->isHttp2Supported() ? 20 : 6;
 
-    QByteArray chunkSizeEnv = qgetenv("OWNCLOUD_CHUNK_SIZE");
-    if (!chunkSizeEnv.isEmpty()) {
-        opt._initialChunkSize = chunkSizeEnv.toUInt();
-    } else {
-        opt._initialChunkSize = cfgFile.chunkSize();
-    }
-    QByteArray minChunkSizeEnv = qgetenv("OWNCLOUD_MIN_CHUNK_SIZE");
-    if (!minChunkSizeEnv.isEmpty()) {
-        opt._minChunkSize = minChunkSizeEnv.toUInt();
-    } else {
-        opt._minChunkSize = cfgFile.minChunkSize();
-    }
-    QByteArray maxChunkSizeEnv = qgetenv("OWNCLOUD_MAX_CHUNK_SIZE");
-    if (!maxChunkSizeEnv.isEmpty()) {
-        opt._maxChunkSize = maxChunkSizeEnv.toUInt();
-    } else {
-        opt._maxChunkSize = cfgFile.maxChunkSize();
-    }
+    opt._initialChunkSize = cfgFile.chunkSize();
+    opt._minChunkSize = cfgFile.minChunkSize();
+    opt._maxChunkSize = cfgFile.maxChunkSize();
+    opt._targetChunkUploadDuration = cfgFile.targetChunkUploadDuration();
 
-    int maxParallel = qgetenv("OWNCLOUD_MAX_PARALLEL").toUInt();
-    opt._parallelNetworkJobs = maxParallel ? maxParallel : _accountState->account()->isHttp2Supported() ? 20 : 6;
+    opt._deltaSyncEnabled = false;
+    opt._deltaSyncMinFileSize = false;
 
-    // Previously min/max chunk size values didn't exist, so users might
-    // have setups where the chunk size exceeds the new min/max default
-    // values. To cope with this, adjust min/max to always include the
-    // initial chunk size value.
-    opt._minChunkSize = qMin(opt._minChunkSize, opt._initialChunkSize);
-    opt._maxChunkSize = qMax(opt._maxChunkSize, opt._initialChunkSize);
-
-    QByteArray targetChunkUploadDurationEnv = qgetenv("OWNCLOUD_TARGET_CHUNK_UPLOAD_DURATION");
-    if (!targetChunkUploadDurationEnv.isEmpty()) {
-        opt._targetChunkUploadDuration = std::chrono::milliseconds(targetChunkUploadDurationEnv.toUInt());
-    } else {
-        opt._targetChunkUploadDuration = cfgFile.targetChunkUploadDuration();
-    }
+    opt.fillFromEnvironmentVariables();
+    opt.verifyChunkSizes();
 
     _engine->setSyncOptions(opt);
 }
diff --git a/src/libsync/CMakeLists.txt b/src/libsync/CMakeLists.txt
index 7e6bee31f..3c38c6374 100644
--- a/src/libsync/CMakeLists.txt
+++ b/src/libsync/CMakeLists.txt
@@ -51,6 +51,7 @@ set(libsync_SRCS
     syncfilestatustracker.cpp
     localdiscoverytracker.cpp
     syncresult.cpp
+    syncoptions.cpp
     theme.cpp
     clientsideencryption.cpp
     clientsideencryptionjobs.cpp
diff --git a/src/libsync/syncoptions.h b/src/libsync/syncoptions.h
index cc792aa9b..57d1969ba 100644
--- a/src/libsync/syncoptions.h
+++ b/src/libsync/syncoptions.h
@@ -27,9 +27,8 @@ namespace OCC {
  */
 struct OWNCLOUDSYNC_EXPORT SyncOptions
 {
-    SyncOptions()
-        : _vfs(new VfsOff)
-    {}
+    SyncOptions();
+    ~SyncOptions();
 
     /** Maximum size (in Bytes) a folder can have without asking for confirmation.
      * -1 means infinite */
@@ -67,7 +66,28 @@ struct OWNCLOUDSYNC_EXPORT SyncOptions
 
     /** The maximum number of active jobs in parallel  */
     int _parallelNetworkJobs = 6;
+
+    /** Whether delta-synchronization is enabled */
+    bool _deltaSyncEnabled = false;
+
+    /** What the minimum file size (in Bytes) is for delta-synchronization */
+    qint64 _deltaSyncMinFileSize = 0;
+
+    /** Reads settings from env vars where available.
+     *
+     * Currently reads _initialChunkSize, _minChunkSize, _maxChunkSize,
+     * _targetChunkUploadDuration, _parallelNetworkJobs.
+     */
+    void fillFromEnvironmentVariables();
+
+    /** Ensure min <= initial <= max
+     *
+     * Previously min/max chunk size values didn't exist, so users might
+     * have setups where the chunk size exceeds the new min/max default
+     * values. To cope with this, adjust min/max to always include the
+     * initial chunk size value.
+     */
+    void verifyChunkSizes();
 };
 
-
 }