diff --git a/Project.toml b/Project.toml
index da131a3..3fe1d09 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,7 +1,7 @@
 name = "MEDYANSimRunner"
 uuid = "b58a3b99-22e3-44d1-b5ea-258f082a6fe8"
 authors = ["nhz2 <nhz2@cornell.edu>"]
-version = "0.4.1"
+version = "0.4.2"
 
 [deps]
 ArgCheck = "dce04be8-c92d-5529-be00-80e4d2c0e197"
@@ -23,5 +23,5 @@ DeepDiffs = "1"
 JSON3 = "1"
 LoggingExtras = "1"
 OrderedCollections = "1"
-SmallZarrGroups = "0.5, 0.6, 0.7"
+SmallZarrGroups = "0.7.1"
 julia = "1.9"
diff --git a/README.md b/README.md
index c37f5f2..3144da4 100644
--- a/README.md
+++ b/README.md
@@ -95,13 +95,13 @@ Random.seed!(collect(reinterpret(UInt64, sha256(job))))
 job_header, state =  setup(job)
 save job_header
 step = 0
-SmallZarrGroups.save_dir(snapshot_zip_file, save_snapshot(step, state))
-state = load_snapshot(step, SmallZarrGroups.load_dir(snapshot_zip_file), state)
+SmallZarrGroups.save_zip(snapshot_zip_file, save_snapshot(step, state))
+state = load_snapshot(step, SmallZarrGroups.load_zip(snapshot_zip_file), state)
 while true
     state = loop(step, state)
     step = step + 1
-    SmallZarrGroups.save_dir(snapshot_zip_file, save_snapshot(step, state))
-    state = load_snapshot(step, SmallZarrGroups.load_dir(snapshot_zip_file), state)
+    SmallZarrGroups.save_zip(snapshot_zip_file, save_snapshot(step, state))
+    state = load_snapshot(step, SmallZarrGroups.load_zip(snapshot_zip_file), state)
     if done(step::Int, state)[1]
         break
     end
diff --git a/src/outputdiff.jl b/src/outputdiff.jl
index cf49584..e8030e0 100644
--- a/src/outputdiff.jl
+++ b/src/outputdiff.jl
@@ -71,8 +71,8 @@ function print_traj_diff(io::IO, jobout1::AbstractString, jobout2::AbstractStrin
         for snapshotname in (snapshots1 ∩ snapshots2)
             full_name1 = joinpath(snapshot1dir, snapshotname)
             full_name2 = joinpath(snapshot2dir, snapshotname)
-            group1 = SmallZarrGroups.load_dir(full_name1)
-            group2 = SmallZarrGroups.load_dir(full_name2)
+            group1 = SmallZarrGroups.load_zip(full_name1)
+            group2 = SmallZarrGroups.load_zip(full_name2)
             SmallZarrGroups.print_diff(io, group1, group2, full_name1, full_name2, "", startswith("#"))
         end
     elseif snapshot1dir_exists && !snapshot2dir_exists
diff --git a/src/run-sim.jl b/src/run-sim.jl
index c05b2c0..3c5b31f 100644
--- a/src/run-sim.jl
+++ b/src/run-sim.jl
@@ -325,14 +325,12 @@ end
 
 function zip_group(g::ZGroup)::Vector{UInt8}
     io = IOBuffer()
-    writer = SmallZarrGroups.ZarrZipWriter(io)
-    SmallZarrGroups.save_dir(writer, g)
-    SmallZarrGroups.closewriter(writer)
+    SmallZarrGroups.save_zip(io, g)
     take!(io)
 end
 
 function unzip_group(data::Vector{UInt8})::ZGroup
-    SmallZarrGroups.load_dir(SmallZarrGroups.ZarrZipReader(data))
+    SmallZarrGroups.load_zip(data)
 end