diff --git a/.circleci/config.yml b/.circleci/config.yml
index bd3564c71c..78d49cf74b 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -7,7 +7,7 @@ executors:
   zenith-build-executor:
     resource_class: xlarge
     docker:
-      - image: cimg/rust:1.52.1
+      - image: cimg/rust:1.55.0
 
 jobs:
   check-codestyle:
@@ -110,7 +110,7 @@ jobs:
             # Require an exact match. While an out of date cache might speed up the build,
             # there's no way to clean out old packages, so the cache grows every time something
             # changes.
-            - v03-rust-cache-deps-<< parameters.build_type >>-{{ checksum "Cargo.lock" }}
+            - v04-rust-cache-deps-<< parameters.build_type >>-{{ checksum "Cargo.lock" }}
 
         # Build the rust code, including test binaries
       - run:
@@ -128,7 +128,7 @@ jobs:
 
       - save_cache:
           name: Save rust cache
-          key: v03-rust-cache-deps-<< parameters.build_type >>-{{ checksum "Cargo.lock" }}
+          key: v04-rust-cache-deps-<< parameters.build_type >>-{{ checksum "Cargo.lock" }}
           paths:
             - ~/.cargo/registry
             - ~/.cargo/git
diff --git a/README.md b/README.md
index 1e0f20fd45..977d015bfc 100644
--- a/README.md
+++ b/README.md
@@ -28,7 +28,7 @@ apt install build-essential libtool libreadline-dev zlib1g-dev flex bison libsec
 libssl-dev clang pkg-config libpq-dev
 ```
 
-[Rust] 1.52 or later is also required.
+[Rust] 1.55 or later is also required.
 
 To run the `psql` client, install the `postgresql-client` package or modify `PATH` and `LD_LIBRARY_PATH` to include `tmp_install/bin` and `tmp_install/lib`, respectively.