diff --git a/.devcontainer/Dockerfile b/.devcontainer/Dockerfile
index fa7a057..de88b3e 100644
--- a/.devcontainer/Dockerfile
+++ b/.devcontainer/Dockerfile
@@ -20,7 +20,7 @@ ADD https://github.com/einar-saukas/ZX0.git /zx0
 RUN cd /zx0/src/ \
 	&& gcc -O2 -o zx0 zx0.c optimize.c compress.c memory.c \
 	&& gcc -O2 -o dzx0 dzx0.c
-ADD https://www.boriel.com/files/zxb/zxbasic-1.18.5-linux64.tar.gz .
+ADD https://www.boriel.com/files/zxb/zxbasic-1.18.6-linux64.tar.gz .
 RUN tar xf zxbasic*
 ADD https://github.com/Mastodon-/inpaws.git /inpaws
 RUN cd /inpaws/ \
diff --git a/.devcontainer/devcontainer.json b/.devcontainer/devcontainer.json
index 38e6904..a971ad9 100644
--- a/.devcontainer/devcontainer.json
+++ b/.devcontainer/devcontainer.json
@@ -2,7 +2,7 @@
 	"name": "ZX Spectrum dev tools",
 	//"build": { "dockerfile": "Dockerfile" },
 	// The Dockerfile takes an age to build due to z88dk, so pull from prebuilt:
-	"image": "boarstone.mcphail.uk/mcphail/speccydev:v5.0",
+	"image": "boarstone.mcphail.uk/mcphail/speccydev:v5.1",
 	"remoteUser": "ubuntu",
 	"runArgs": [
 		"--network=host"
diff --git a/README.md b/README.md
index a1331ba..ef1235e 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,4 @@
-# Development tools for the ZX Spectrum v5.0
+# Development tools for the ZX Spectrum v5.1
 
 The Dockerfile is the basis of the devcontainer and can be changed to add or remove tools. It will take a long time to build locally, so by default the devcontainer will pull a prebuilt version. Edit `.devcontainer/devcontainer.json` if you would rather build your own.
 
@@ -29,7 +29,7 @@ The devcontainer contains:
     - tzxlist
 - zx0 (binary compressor)
 - dzx0 (binary decompressor)
-- ZX BASIC (aka Boriel BASIC) version 1.18.5
+- ZX BASIC (aka Boriel BASIC) version 1.18.6
     - zxbc (BASIC compiler)
     - zxbasm (assembler)
     - zxbpp (preprocessor)
@@ -66,9 +66,9 @@ Thanks to the many authors of these wonderful tools and extensions; to think wha
 
 Boriel BASIC (zxbasic) has been updated. There have been further bug fixes to array bounds which may break old code reliant on previous behaviour.
 
-## New additions from v4.x
+## New additions from v5.0
 
-`sjasmplus` has been updated with new features.
+Boriel BASIC updated for hotfix for broken zxnext builds.
 
 ## Install