diff --git a/Dockerfile b/Dockerfile
index 1c120f0..e37c137 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,7 +1,7 @@
 FROM buildpack-deps:bookworm AS builder-base
 LABEL org.opencontainers.image.authors="Joe Banks <joe@owlcorp.uk>, Chris Lovering <cj@owlcorp.uk>"
 
-ARG PYENV_VERSION="v2.6.11"
+ARG PYENV_VERSION="v2.8.4"
 
 RUN apt-get -y update \
     && apt-get install -y --no-install-recommends \
@@ -15,7 +15,7 @@ RUN apt-get -y update \
 # Following guidance from https://github.com/python/cpython/blob/main/Tools/jit/README.md
 RUN curl -o /tmp/llvm.sh https://apt.llvm.org/llvm.sh \
     && chmod +x /tmp/llvm.sh \
-    && /tmp/llvm.sh 19 \
+    && /tmp/llvm.sh 22 \
     && rm /tmp/llvm.sh
 
 ENV PYENV_ROOT=/pyenv \
diff --git a/scripts/find_version.py b/scripts/find_version.py
index 2457eea..4c1d059 100644
--- a/scripts/find_version.py
+++ b/scripts/find_version.py
@@ -1,7 +1,9 @@
-from pathlib import Path
-import tomllib
 import json
 import os
+from pathlib import Path
+
+import tomllib
+
 
 def resolve_version(friendly_version: str) -> str:
     """Resolve a friendly version like '3.10t' to an exact version like '3.10.12'."""
@@ -29,8 +31,14 @@ def resolve_version(friendly_version: str) -> str:
     if not matching_versions:
         raise ValueError(f"No matching versions found for base version '{base_version}'")
 
-    # Sort versions to get the latest
-    matching_versions.sort(key=lambda s: list(map(int, s.split('.'))))
+    def version_sort_key(s):
+        def part_key(p):
+            n, *rc = p.split('rc')
+            # rc suffix sorts below final release (no rc = inf)
+            return (int(n), int(rc[0]) if rc else float('inf'))
+        return [part_key(p) for p in s.split('.')]
+
+    matching_versions.sort(key=version_sort_key)
 
     latest_version = matching_versions[-1]
 
diff --git a/versions.toml b/versions.toml
index 10d2b52..7e491af 100644
--- a/versions.toml
+++ b/versions.toml
@@ -16,6 +16,9 @@
 
 [config]
 versions = [
+    "3.15",
+    "3.15t",
+    "3.15j",
     "3.14",
     "3.14t",
     "3.14j",
@@ -23,5 +26,4 @@ versions = [
     "3.13t",
     "3.12",
     "3.11",
-    "3.10",
 ]