diff --git a/.github/workflows/cygwin-510.yml b/.github/workflows/cygwin-51x.yml
similarity index 81%
rename from .github/workflows/cygwin-510.yml
rename to .github/workflows/cygwin-51x.yml
index 54870c80e..df4b9b915 100644
--- a/.github/workflows/cygwin-510.yml
+++ b/.github/workflows/cygwin-51x.yml
@@ -7,7 +7,7 @@ jobs:
     uses: ./.github/workflows/common.yml
     with:
       runs_on: windows-latest
-      compiler: ocaml-variants.5.1.0+options+win
+      compiler: ocaml-variants.5.1.1~rc1+options+win
       cygwin: true
       timeout: 360
       dune_alias: 'ci1'
@@ -18,7 +18,7 @@ jobs:
     uses: ./.github/workflows/common.yml
     with:
       runs_on: windows-latest
-      compiler: ocaml-variants.5.1.0+options+win
+      compiler: ocaml-variants.5.1.1~rc1+options+win
       cygwin: true
       timeout: 360
       dune_alias: 'ci2'
diff --git a/.github/workflows/linux-510-32bit.yml b/.github/workflows/linux-51x-32bit.yml
similarity index 67%
rename from .github/workflows/linux-510-32bit.yml
rename to .github/workflows/linux-51x-32bit.yml
index 988397056..7df54afb7 100644
--- a/.github/workflows/linux-510-32bit.yml
+++ b/.github/workflows/linux-51x-32bit.yml
@@ -6,5 +6,5 @@ jobs:
   build:
     uses: ./.github/workflows/common.yml
     with:
-      compiler: 'ocaml-variants.5.1.0+options,ocaml-option-32bit'
+      compiler: 'ocaml-variants.5.1.1~rc1+options,ocaml-option-32bit'
       timeout: 240
diff --git a/.github/workflows/linux-510-bytecode.yml b/.github/workflows/linux-51x-bytecode.yml
similarity index 65%
rename from .github/workflows/linux-510-bytecode.yml
rename to .github/workflows/linux-51x-bytecode.yml
index 43b2610a6..78c48a5d5 100644
--- a/.github/workflows/linux-510-bytecode.yml
+++ b/.github/workflows/linux-51x-bytecode.yml
@@ -6,5 +6,5 @@ jobs:
   build:
     uses: ./.github/workflows/common.yml
     with:
-      compiler: 'ocaml-variants.5.1.0+options,ocaml-option-bytecode-only'
+      compiler: 'ocaml-variants.5.1.1~rc1+options,ocaml-option-bytecode-only'
       timeout: 240
diff --git a/.github/workflows/linux-510-debug.yml b/.github/workflows/linux-51x-debug.yml
similarity index 82%
rename from .github/workflows/linux-510-debug.yml
rename to .github/workflows/linux-51x-debug.yml
index 3e9dfee26..6724568b5 100644
--- a/.github/workflows/linux-510-debug.yml
+++ b/.github/workflows/linux-51x-debug.yml
@@ -6,7 +6,7 @@ jobs:
   build:
     uses: ./.github/workflows/common.yml
     with:
-      compiler: 'ocaml-base-compiler.5.1.0'
+      compiler: 'ocaml-base-compiler.5.1.1~rc1'
       dune_profile: 'debug-runtime'
       runparam: 's=4096,v=0,V=1'
       timeout: 240
diff --git a/.github/workflows/linux-510-fp.yml b/.github/workflows/linux-51x-fp.yml
similarity index 68%
rename from .github/workflows/linux-510-fp.yml
rename to .github/workflows/linux-51x-fp.yml
index bd6507062..2fb76dc1c 100644
--- a/.github/workflows/linux-510-fp.yml
+++ b/.github/workflows/linux-51x-fp.yml
@@ -6,5 +6,5 @@ jobs:
   build:
     uses: ./.github/workflows/common.yml
     with:
-      compiler: 'ocaml-variants.5.1.0+options,ocaml-option-fp'
+      compiler: 'ocaml-variants.5.1.1~rc1+options,ocaml-option-fp'
       timeout: 240
diff --git a/.github/workflows/linux-510.yml b/.github/workflows/linux-51x.yml
similarity index 72%
rename from .github/workflows/linux-510.yml
rename to .github/workflows/linux-51x.yml
index 5c8762bd4..a09deb9a6 100644
--- a/.github/workflows/linux-510.yml
+++ b/.github/workflows/linux-51x.yml
@@ -6,4 +6,4 @@ jobs:
   build:
     uses: ./.github/workflows/common.yml
     with:
-      compiler: 'ocaml-base-compiler.5.1.0'
+      compiler: 'ocaml-base-compiler.5.1.1~rc1'
diff --git a/.github/workflows/macosx-510.yml b/.github/workflows/macosx-51x.yml
similarity index 76%
rename from .github/workflows/macosx-510.yml
rename to .github/workflows/macosx-51x.yml
index dc535fc31..d71042f93 100644
--- a/.github/workflows/macosx-510.yml
+++ b/.github/workflows/macosx-51x.yml
@@ -6,5 +6,5 @@ jobs:
   build:
     uses: ./.github/workflows/common.yml
     with:
-      compiler: 'ocaml-base-compiler.5.1.0'
+      compiler: 'ocaml-base-compiler.5.1.1~rc1'
       runs_on: 'macos-latest'
diff --git a/.github/workflows/mingw-510-bytecode.yml b/.github/workflows/mingw-51x-bytecode.yml
similarity index 65%
rename from .github/workflows/mingw-510-bytecode.yml
rename to .github/workflows/mingw-51x-bytecode.yml
index 8b29af8f8..efcd97d98 100644
--- a/.github/workflows/mingw-510-bytecode.yml
+++ b/.github/workflows/mingw-51x-bytecode.yml
@@ -7,5 +7,5 @@ jobs:
     uses: ./.github/workflows/common.yml
     with:
       runs_on: windows-latest
-      compiler: ocaml-variants.5.1.0+options+win,ocaml-option-mingw,ocaml-option-bytecode-only
+      compiler: ocaml-variants.5.1.1~rc1+options+win,ocaml-option-mingw,ocaml-option-bytecode-only
       timeout: 240
diff --git a/.github/workflows/mingw-510.yml b/.github/workflows/mingw-51x.yml
similarity index 71%
rename from .github/workflows/mingw-510.yml
rename to .github/workflows/mingw-51x.yml
index 2a1e6f8d8..34699c879 100644
--- a/.github/workflows/mingw-510.yml
+++ b/.github/workflows/mingw-51x.yml
@@ -7,5 +7,5 @@ jobs:
     uses: ./.github/workflows/common.yml
     with:
       runs_on: windows-latest
-      compiler: ocaml-variants.5.1.0+options+win,ocaml-option-mingw
+      compiler: ocaml-variants.5.1.1~rc1+options+win,ocaml-option-mingw
       timeout: 240
diff --git a/README.md b/README.md
index b75acac7b..d871d7cfb 100644
--- a/README.md
+++ b/README.md
@@ -11,15 +11,15 @@ Multicore tests
 [![MinGW 5.0.0](https://github.com/ocaml-multicore/multicoretests/actions/workflows/mingw-500.yml/badge.svg)](https://github.com/ocaml-multicore/multicoretests/actions/workflows/mingw-500.yml)
 [![MinGW 5.0.0-bytecode](https://github.com/ocaml-multicore/multicoretests/actions/workflows/mingw-500-bytecode.yml/badge.svg)](https://github.com/ocaml-multicore/multicoretests/actions/workflows/mingw-500-bytecode.yml)
 
-[![Linux 5.1.0](https://github.com/ocaml-multicore/multicoretests/actions/workflows/linux-510.yml/badge.svg)](https://github.com/ocaml-multicore/multicoretests/actions/workflows/linux-510.yml)
-[![MacOSX 5.1.0](https://github.com/ocaml-multicore/multicoretests/actions/workflows/macosx-510.yml/badge.svg)](https://github.com/ocaml-multicore/multicoretests/actions/workflows/macosx-510.yml)
-[![Linux 5.1.0-bytecode](https://github.com/ocaml-multicore/multicoretests/actions/workflows/linux-510-bytecode.yml/badge.svg)](https://github.com/ocaml-multicore/multicoretests/actions/workflows/linux-510-bytecode.yml)
-[![Linux 5.1.0-debug](https://github.com/ocaml-multicore/multicoretests/actions/workflows/linux-510-debug.yml/badge.svg)](https://github.com/ocaml-multicore/multicoretests/actions/workflows/linux-510-debug.yml)
-[![Linux 32-bit 5.1.0](https://github.com/ocaml-multicore/multicoretests/actions/workflows/linux-510-32bit.yml/badge.svg)](https://github.com/ocaml-multicore/multicoretests/actions/workflows/linux-510-32bit.yml)
-[![Linux FP 5.1.0](https://github.com/ocaml-multicore/multicoretests/actions/workflows/linux-510-fp.yml/badge.svg)](https://github.com/ocaml-multicore/multicoretests/actions/workflows/linux-510-fp.yml)
-[![MinGW 5.1.0](https://github.com/ocaml-multicore/multicoretests/actions/workflows/mingw-510.yml/badge.svg)](https://github.com/ocaml-multicore/multicoretests/actions/workflows/mingw-510.yml)
-[![MinGW 5.1.0-bytecode](https://github.com/ocaml-multicore/multicoretests/actions/workflows/mingw-510-bytecode.yml/badge.svg)](https://github.com/ocaml-multicore/multicoretests/actions/workflows/mingw-510-bytecode.yml)
-[![Cygwin 5.1.0](https://github.com/ocaml-multicore/multicoretests/actions/workflows/cygwin-510.yml/badge.svg)](https://github.com/ocaml-multicore/multicoretests/actions/workflows/cygwin-510.yml)
+[![Linux 5.1.0](https://github.com/ocaml-multicore/multicoretests/actions/workflows/linux-51x.yml/badge.svg)](https://github.com/ocaml-multicore/multicoretests/actions/workflows/linux-51x.yml)
+[![MacOSX 5.1.0](https://github.com/ocaml-multicore/multicoretests/actions/workflows/macosx-51x.yml/badge.svg)](https://github.com/ocaml-multicore/multicoretests/actions/workflows/macosx-51x.yml)
+[![Linux 5.1.0-bytecode](https://github.com/ocaml-multicore/multicoretests/actions/workflows/linux-51x-bytecode.yml/badge.svg)](https://github.com/ocaml-multicore/multicoretests/actions/workflows/linux-51x-bytecode.yml)
+[![Linux 5.1.0-debug](https://github.com/ocaml-multicore/multicoretests/actions/workflows/linux-51x-debug.yml/badge.svg)](https://github.com/ocaml-multicore/multicoretests/actions/workflows/linux-51x-debug.yml)
+[![Linux 32-bit 5.1.0](https://github.com/ocaml-multicore/multicoretests/actions/workflows/linux-51x-32bit.yml/badge.svg)](https://github.com/ocaml-multicore/multicoretests/actions/workflows/linux-51x-32bit.yml)
+[![Linux FP 5.1.0](https://github.com/ocaml-multicore/multicoretests/actions/workflows/linux-51x-fp.yml/badge.svg)](https://github.com/ocaml-multicore/multicoretests/actions/workflows/linux-51x-fp.yml)
+[![MinGW 5.1.0](https://github.com/ocaml-multicore/multicoretests/actions/workflows/mingw-51x.yml/badge.svg)](https://github.com/ocaml-multicore/multicoretests/actions/workflows/mingw-51x.yml)
+[![MinGW 5.1.0-bytecode](https://github.com/ocaml-multicore/multicoretests/actions/workflows/mingw-51x-bytecode.yml/badge.svg)](https://github.com/ocaml-multicore/multicoretests/actions/workflows/mingw-51x-bytecode.yml)
+[![Cygwin 5.1.0](https://github.com/ocaml-multicore/multicoretests/actions/workflows/cygwin-51x.yml/badge.svg)](https://github.com/ocaml-multicore/multicoretests/actions/workflows/cygwin-51x.yml)
 
 [![Linux 5.2.0+trunk](https://github.com/ocaml-multicore/multicoretests/actions/workflows/linux-520-trunk.yml/badge.svg)](https://github.com/ocaml-multicore/multicoretests/actions/workflows/linux-520-trunk.yml)
 [![MacOSX 5.2.0+trunk](https://github.com/ocaml-multicore/multicoretests/actions/workflows/macosx-520-trunk.yml/badge.svg)](https://github.com/ocaml-multicore/multicoretests/actions/workflows/macosx-520-trunk.yml)