add 3.5, 3.6. Remove 2.6, 2.5, 2.4

Add newly supported versions and remove intermediate 2.x versions to
lighten the build load.

.github/workflows/main.yml

@@ -12,7 +12,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        zephyr_version: [3.4.0, 2.7.3, 2.6.0, 2.5.0, 2.4.0, 2.3.0]
+        zephyr_version: [3.6.0, 3.5.0, 3.4.0, 2.7.3, 2.3.0]
         board: [qemu_x86, qemu_cortex_m3, qemu_cortex_r5, nucleo_l552ze_q, native_posix, qemu_riscv32, qemu_riscv64]
         test: [samples/rust-app, samples/no_std, samples/serial]
         exclude:

README.rst

@@ -10,10 +10,15 @@ Zephyr app.
 
 Version Compatibility
 =====================
-**Zephyr**: v2.3, v2.4, v2.5, v2.6, v2.7, v3.4
+**Zephyr**: v2.3, v2.7.3, v3.4, v3.5, v3.6
 
 **Rust**: exactly 1.68.0
 
+Please use one of the above Zephyr releases before reporting issues! At the
+time you are reading this, Zephyr's main branch will likely not work, though it
+is usually one 1-2 minor changes to support a new release. The project aims to
+support everything from 2.3 to the present.
+
 Features
 ========
 

ci/build-all.sh

@@ -2,7 +2,7 @@
 
 #rm -rf log
 
-ZEPHYR_VERSIONS="3.4.0 2.7.3 2.6.0 2.5.0 2.4.0 2.3.0"
+ZEPHYR_VERSIONS="3.6.0 3.5.0 3.4.0 2.7.3 2.3.0"
 
 #parallel \
 #    -j8 \