diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..b25c15b
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+*~
diff --git a/chunker b/chunker
index 7075179..0c4ec01 100755
--- a/chunker
+++ b/chunker
@@ -28,7 +28,7 @@ mkdir -p "$CHUNKER_WORKING_DIR/current" || exit 1
 cur_size=$( du -B1 -s "$CHUNKER_WORKING_DIR/current" | grep -oE "^[0-9]+" )
 
 # find every .warc.gz in the upload directory
-find "$INCOMING_UPLOADS_DIR" -type f -name "*.warc.gz" \
+find "$INCOMING_UPLOADS_DIR" -type f -regex ".+\.warc\.\(gz\|zst\)$" \
 | while read filename
 do
   # skip partial uploads
diff --git a/config.example.sh b/config.example.sh
index 26be8ca..9875f1d 100755
--- a/config.example.sh
+++ b/config.example.sh
@@ -34,6 +34,9 @@ OFFLOAD_TARGET="rsync://somewhere-far-away:portnum/module-name/directory/"
 # it is also possible to create a list of targets and the offloader will pick one at random and retry others on failure
 # simply comment out the line above and put all rsync target urls separated by newline in a file called "offload_targets"
 
+# the API for requesting the ZSTD dictionaries
+ZST_DICTIONARY_API="API URL"
+
 ###############
 # DIRECTORIES #
 ###############
diff --git a/megawarc b/megawarc
index f77638d..5468d80 160000
--- a/megawarc
+++ b/megawarc
@@ -1 +1 @@
-Subproject commit f77638dbf7d0c4a7dd301217ee04fbc6a3c3ebbf
+Subproject commit 5468d80e35b3dcb85d36624580c813326af706fe
diff --git a/pack-one b/pack-one
index b798e77..ea496c6 100755
--- a/pack-one
+++ b/pack-one
@@ -84,7 +84,7 @@ echo "$( date ): Starting megawarc for item $ITEM" >> packer.log
 mkdir -p $PACKER_WORKING_MEGAWARC_DIR/$ITEM
 # megawarcs use relative paths
 cd "$PACKER_WORKING_CHUNKS_DIR/"
-$MEGAWARC --verbose pack $PACKER_WORKING_MEGAWARC_DIR/$ITEM/${FILE_PREFIX}${ITEM} $ITEM
+$MEGAWARC --verbose pack --server $ZST_DICTIONARY_API $PACKER_WORKING_MEGAWARC_DIR/$ITEM/${FILE_PREFIX}${ITEM} $ITEM
 result=$?
 cd "$WORKING_DIR"
 
diff --git a/upload-one b/upload-one
index 360dfd9..6359c1a 100755
--- a/upload-one
+++ b/upload-one
@@ -65,13 +65,13 @@ echo "$( date ): Start uploading for item $ITEM" >> uploader.log
 # upload megawarc
 size_hint=$( du --bytes -s "${UPLOADER_WORKING_DIR}/${ITEM}" | grep -oE "^[0-9]+" )
 # (upload the large files first to optimise S3 snowballing)
-for ext in warc.gz tar json.gz
+
+find "${UPLOADER_WORKING_DIR}/${ITEM}" -type f -regextype posix-egrep -regex ".+\.megawarc\.(warc\.(gz|zst)|tar|json\.gz)$" -printf "%f\n" \
+| while read filename
 do
-  test "${ext}" == "tar" && ! test -f "${FILE_PREFIX}${ITEM}.megawarc.${ext}" && continue # skip non-existing tar files
   result=1
   while [[ $result -ne 0 ]]
   do
-    filename="${FILE_PREFIX}${ITEM}.megawarc.${ext}"
     curl -v --location --fail \
       --speed-limit 1 --speed-time 900 \
       --header "x-archive-queue-derive:1" \