diff --git a/Dockerfile b/Dockerfile
index c5c2d27a..e7351a5d 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,6 +1,6 @@
-FROM ocaml/opam:debian-11-ocaml-4.14@sha256:5b9de826b22c77a0654519d0959536f93a6ffd7020712a8b1c3437445e031e04 AS build
+FROM ocaml/opam:debian-11-ocaml-4.14@sha256:698cd4a3d59912f89deb3c8cb05b9299a870b27086d212877f5f3c88f4021b74 AS build
 RUN sudo apt-get update && sudo apt-get install libev-dev capnproto m4 pkg-config libsqlite3-dev libgmp-dev -y --no-install-recommends
-RUN cd ~/opam-repository && git pull origin -q master && git reset --hard 97da9a1b68b824a65a09e5f7d071fcf2da35bd1b && opam update
+RUN cd ~/opam-repository && git fetch -q origin master && git reset --hard 57f1b681ce75766a17f15588c2088174edbb89c9 && opam update
 COPY --chown=opam ocluster-api.opam ocluster.opam /src/
 COPY --chown=opam obuilder/obuilder.opam obuilder/obuilder-spec.opam /src/obuilder/
 RUN opam pin -yn /src/obuilder/
diff --git a/Dockerfile.worker b/Dockerfile.worker
index b72bde6d..14920bef 100644
--- a/Dockerfile.worker
+++ b/Dockerfile.worker
@@ -1,6 +1,6 @@
-FROM ocaml/opam:ubuntu-22.04-ocaml-4.14@sha256:1d783d4caa30a9e2913d05aa0e80f803af02f04e3124d38a148c92a3f9ac1bbc AS build
+FROM ocaml/opam:ubuntu-22.04-ocaml-4.14@sha256:3d379b4a575d050ea02b1146f03d7ab28ccf15e6fecdada5595b0b04a8a307d0 AS build
 RUN sudo apt-get update && sudo apt-get install libev-dev capnproto m4 pkg-config libsqlite3-dev libgmp-dev -y --no-install-recommends
-RUN cd ~/opam-repository && git pull origin -q master && git reset --hard 97da9a1b68b824a65a09e5f7d071fcf2da35bd1b && opam update
+RUN cd ~/opam-repository && git fetch -q origin master && git reset --hard 57f1b681ce75766a17f15588c2088174edbb89c9 && opam update
 COPY --chown=opam ocluster-api.opam ocluster.opam /src/
 COPY --chown=opam obuilder/obuilder.opam obuilder/obuilder-spec.opam /src/obuilder/
 RUN opam pin -yn /src/obuilder/
diff --git a/bin/worker.ml b/bin/worker.ml
index 82fc1d42..d7cbd76d 100644
--- a/bin/worker.ml
+++ b/bin/worker.ml
@@ -69,7 +69,7 @@ let worker_name =
   Arg.required @@
   Arg.opt Arg.(some string) None @@
   Arg.info
-    ~doc:"Unique builder name"
+    ~doc:"Unique builder name."
     ~docv:"ID"
     ["name"]
 
@@ -77,7 +77,7 @@ let connect_addr =
   Arg.required @@
   Arg.opt Arg.(some file) None @@
   Arg.info
-    ~doc:"Path of register.cap from build-scheduler"
+    ~doc:"Path of register.cap from build-scheduler."
     ~docv:"ADDR"
     ["c"; "connect"]
 
@@ -85,7 +85,7 @@ let capacity =
   Arg.value @@
   Arg.opt Arg.int 10 @@
   Arg.info
-    ~doc:"The number of builds that can run in parallel"
+    ~doc:"The number of builds that can run in parallel."
     ~docv:"N"
     ["capacity"]
 
@@ -94,7 +94,7 @@ let prune_threshold =
   Arg.opt Arg.(some float) None @@
   Arg.info
     ~doc:"Run 'docker system prune' when /var/lib/docker's free space falls below this (0-100). \
-          If you don't have a partition for /var/lib/docker, then you can use docker-max-df-size."
+          If you don't have a partition for /var/lib/docker, then you can use $(b,--docker-max-df-size)."
     ~docv:"PERCENTAGE"
     ["prune-threshold"]
 
@@ -111,7 +111,7 @@ let obuilder_prune_threshold =
   Arg.value @@
   Arg.opt Arg.(some float) None @@
   Arg.info
-    ~doc:"If using OBuilder, this threshold is used to prune the stored builds if the free space falls below this (0-100)"
+    ~doc:"If using OBuilder, this threshold is used to prune the stored builds if the free space falls below this (0-100)."
     ~docv:"PERCENTAGE"
     ["obuilder-prune-threshold"]
 
@@ -119,7 +119,7 @@ let allow_push =
   Arg.value @@
   Arg.opt Arg.(list string) [] @@
   Arg.info
-    ~doc:"Docker repositories to which users can push"
+    ~doc:"Docker repositories to which users can push."
     ~docv:"REPO"
     ["allow-push"]
 
@@ -127,7 +127,7 @@ let state_dir =
   Arg.required @@
   Arg.opt Arg.(some string) None @@
   Arg.info
-    ~doc:"Directory for caches, etc (e.g. /var/lib/ocluster-worker)"
+    ~doc:"Directory for caches, etc (e.g. /var/lib/ocluster-worker)."
     ~docv:"PATH"
     ["state-dir"]
 
@@ -138,7 +138,7 @@ module Obuilder_config = struct
     Arg.value @@
     Arg.opt Arg.(some store_t) None @@
     Arg.info
-      ~doc:"btrfs:/path or rsync:/path or zfs:pool for the OBuilder cache"
+      ~doc:"btrfs:/path or rsync:/path or zfs:pool for the OBuilder cache."
       ~docv:"STORE"
       ["obuilder-store"]
 
diff --git a/obuilder b/obuilder
index 0c41ec91..4a8530ed 160000
--- a/obuilder
+++ b/obuilder
@@ -1 +1 @@
-Subproject commit 0c41ec9164ec246f53e6d22df5a2f6ee240d797f
+Subproject commit 4a8530ed9dd24c1b36a202918e36c898fff92613