When testing khem's patches for binutils-2.23 I've noticed that after building both versions (2.22 and 2.23) I cannot switch between them by changing BINUVERSION.

Bitbake says:
NOTE: Tasks Summary: Attempted 82 tasks of which 82 didn't need to be rerun and all succeeded.
and last version built stays in sysroot forever (unless I clean stamps manually e.g. with -c cleansstate).

bluelightning said that at least populate-sysroot stamp should be removed when different version is built.

Build log showing it wasn't removed:
OE qemux86-64@ ~/oe-core $ ls -lah tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.23-r0.do_*
-rw-r--r-- 1 bitbake bitbake    0 Aug 17 11:33 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.23-r0.do_build
-rw-r--r-- 1 bitbake bitbake    0 Aug 17 11:33 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.23-r0.do_compile
-rw-rw-r-- 1 bitbake bitbake  18K Aug 17 11:33 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.23-r0.do_compile.sigdata.8d9ab34ded1404b2be128be3e256ed8b
-rw-r--r-- 1 bitbake bitbake    0 Aug 17 11:32 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.23-r0.do_configure
-rw-rw-r-- 1 bitbake bitbake  23K Aug 17 11:32 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.23-r0.do_configure.sigdata.baf089614fe66512d9aedf3ce3618482
-rw-r--r-- 1 bitbake bitbake    0 Aug 17 11:31 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.23-r0.do_fetch
-rw-rw-r-- 1 bitbake bitbake 3.7K Aug 17 11:31 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.23-r0.do_fetch.sigdata.36c7fa53961686f5c07990bcde8d9c5e
-rw-r--r-- 1 bitbake bitbake    0 Aug 17 11:33 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.23-r0.do_install
-rw-rw-r-- 1 bitbake bitbake  20K Aug 17 11:33 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.23-r0.do_install.sigdata.c6a6448480f41fdc2611b2d49dc54e0e
-rw-r--r-- 1 bitbake bitbake    0 Aug 17 11:33 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.23-r0.do_package.qemux86-64
-rw-rw-r-- 1 bitbake bitbake 107K Aug 17 11:33 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.23-r0.do_package.sigdata.c1555fb8f7a9e84199f65bf65650b63b
-rw-r--r-- 1 bitbake bitbake    0 Aug 17 11:33 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.23-r0.do_package_write
-rw-r--r-- 1 bitbake bitbake    0 Aug 17 11:33 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.23-r0.do_package_write_ipk
-rw-rw-r-- 1 bitbake bitbake  12K Aug 17 11:33 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.23-r0.do_package_write_ipk.sigdata.e0e3df9bbb060b43487198d26eddb82f
-rw-r--r-- 1 bitbake bitbake    0 Aug 17 11:31 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.23-r0.do_patch
-rw-rw-r-- 1 bitbake bitbake 7.3K Aug 17 11:31 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.23-r0.do_patch.sigdata.85f190de6a4faae5cad7b4956f408b6b
-rw-r--r-- 1 bitbake bitbake    0 Aug 17 11:32 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.23-r0.do_populate_lic
-rw-rw-r-- 1 bitbake bitbake 8.4K Aug 17 11:32 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.23-r0.do_populate_lic.sigdata.0b1ec8929ab56acda421916477c51f3c
-rw-r--r-- 1 bitbake bitbake    0 Aug 17 11:33 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.23-r0.do_populate_sysroot.qemux86-64
-rw-rw-r-- 1 bitbake bitbake  21K Aug 17 11:33 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.23-r0.do_populate_sysroot.sigdata.68dd391c46bfc12987cb545fddd5eeca
-rw-r--r-- 1 bitbake bitbake    0 Aug 17 11:31 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.23-r0.do_unpack
-rw-rw-r-- 1 bitbake bitbake 2.1K Aug 17 11:31 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.23-r0.do_unpack.sigdata.cdb642480037af2182aca8d2f0882547
OE qemux86-64@ ~/oe-core $ bitbake -k binutils-cross | tee log.binutils
Loading cache...done.
Loaded 1131 entries from dependency cache.

Build Configuration:
BB_VERSION        = "1.15.3"
TARGET_ARCH       = "x86_64"
TARGET_OS         = "linux"
MACHINE           = "qemux86-64"
DISTRO_VERSION    = "oe-core.0"
TUNE_FEATURES     = "m64"
TARGET_FPU        = ""
meta              = "jansa/test:f1e2865d19226deabca0f402cebf5b92472f6073"

NOTE: Resolving any missing task queue dependencies
NOTE: Preparing runqueue
NOTE: Executing SetScene Tasks
NOTE: Executing RunQueue Tasks
NOTE: Tasks Summary: Attempted 82 tasks of which 82 didn't need to be rerun and all succeeded.

OE qemux86-64@ ~/oe-core $ bitbake -k binutils-cross | tee log.binutils
Parsing recipes...done.
Parsing of 831 .bb files complete (0 cached, 831 parsed). 1130 targets, 20 skipped, 0 masked, 0 errors.

Build Configuration:
BB_VERSION        = "1.15.3"
TARGET_ARCH       = "x86_64"
TARGET_OS         = "linux"
MACHINE           = "qemux86-64"
DISTRO_VERSION    = "oe-core.0"
TUNE_FEATURES     = "m64"
TARGET_FPU        = ""
meta              = "jansa/test:f1e2865d19226deabca0f402cebf5b92472f6073"
NOTE: Resolving any missing task queue dependencies
NOTE: Preparing runqueue
NOTE: Executing SetScene Tasks
NOTE: Executing RunQueue Tasks
NOTE: Running task 50 of 82 (ID: 4, /OE/oe-core/openembedded-core/meta/recipes-devtools/binutils/binutils-cross_2.22.bb, do_fetch)
NOTE: package binutils-cross-2.22-r14: task do_fetch: Started
NOTE: package binutils-cross-2.22-r14: task do_fetch: Succeeded
NOTE: Running task 72 of 82 (ID: 0, /OE/oe-core/openembedded-core/meta/recipes-devtools/binutils/binutils-cross_2.22.bb, do_unpack)
NOTE: package binutils-cross-2.22-r14: task do_unpack: Started
NOTE: package binutils-cross-2.22-r14: task do_unpack: Succeeded
NOTE: Running task 73 of 82 (ID: 1, /OE/oe-core/openembedded-core/meta/recipes-devtools/binutils/binutils-cross_2.22.bb, do_patch)
NOTE: package binutils-cross-2.22-r14: task do_patch: Started
NOTE: package binutils-cross-2.22-r14: task do_patch: Succeeded
NOTE: Running task 74 of 82 (ID: 5, /OE/oe-core/openembedded-core/meta/recipes-devtools/binutils/binutils-cross_2.22.bb, do_configure)
NOTE: Running task 75 of 82 (ID: 10, /OE/oe-core/openembedded-core/meta/recipes-devtools/binutils/binutils-cross_2.22.bb, do_populate_lic)
NOTE: package binutils-cross-2.22-r14: task do_populate_lic: Started
NOTE: package binutils-cross-2.22-r14: task do_configure: Started
NOTE: package binutils-cross-2.22-r14: task do_populate_lic: Succeeded
NOTE: package binutils-cross-2.22-r14: task do_configure: Succeeded
NOTE: Running task 76 of 82 (ID: 6, /OE/oe-core/openembedded-core/meta/recipes-devtools/binutils/binutils-cross_2.22.bb, do_compile)
NOTE: package binutils-cross-2.22-r14: task do_compile: Started
NOTE: package binutils-cross-2.22-r14: task do_compile: Succeeded
NOTE: Running task 77 of 82 (ID: 2, /OE/oe-core/openembedded-core/meta/recipes-devtools/binutils/binutils-cross_2.22.bb, do_install)
NOTE: package binutils-cross-2.22-r14: task do_install: Started
NOTE: package binutils-cross-2.22-r14: task do_install: Succeeded
NOTE: Running task 78 of 82 (ID: 8, /OE/oe-core/openembedded-core/meta/recipes-devtools/binutils/binutils-cross_2.22.bb, do_package)
NOTE: Running task 79 of 82 (ID: 3, /OE/oe-core/openembedded-core/meta/recipes-devtools/binutils/binutils-cross_2.22.bb, do_populate_sysroot)
NOTE: package binutils-cross-2.22-r14: task do_package: Started
NOTE: package binutils-cross-2.22-r14: task do_populate_sysroot: Started
NOTE: package binutils-cross-2.22-r14: task do_package: Succeeded
NOTE: Running task 80 of 82 (ID: 11, /OE/oe-core/openembedded-core/meta/recipes-devtools/binutils/binutils-cross_2.22.bb, do_package_write_ipk)
NOTE: package binutils-cross-2.22-r14: task do_package_write_ipk: Started
NOTE: package binutils-cross-2.22-r14: task do_package_write_ipk: Succeeded
NOTE: Running noexec task 81 of 82 (ID: 7, /OE/oe-core/openembedded-core/meta/recipes-devtools/binutils/binutils-cross_2.22.bb, do_package_write)
NOTE: package binutils-cross-2.22-r14: task do_populate_sysroot: Succeeded
NOTE: Running noexec task 82 of 82 (ID: 9, /OE/oe-core/openembedded-core/meta/recipes-devtools/binutils/binutils-cross_2.22.bb, do_build)
NOTE: Tasks Summary: Attempted 82 tasks of which 70 didn't need to be rerun and all succeeded.

OE qemux86-64@ ~/oe-core $ tmp-eglibc/sysroots/x86_64-linux/usr/bin/x86_64-oe-linux/x86_64-oe-linux-ld -v
GNU ld (GNU Binutils) 2.22

good sofar

OE qemux86-64@ ~/oe-core $ ls -lah tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross*
-rw-r--r-- 1 bitbake bitbake    0 Aug 17 11:40 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.22-r14.do_build
-rw-r--r-- 1 bitbake bitbake    0 Aug 17 11:40 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.22-r14.do_compile
-rw-rw-r-- 1 bitbake bitbake  18K Aug 17 11:40 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.22-r14.do_compile.sigdata.bc0efed68cba4c316bb3b027aafd703c
-rw-r--r-- 1 bitbake bitbake    0 Aug 17 11:39 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.22-r14.do_configure
-rw-rw-r-- 1 bitbake bitbake  23K Aug 17 11:39 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.22-r14.do_configure.sigdata.3135daf0c82427ac06e35e29b971b441
-rw-r--r-- 1 bitbake bitbake    0 Aug 17 11:39 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.22-r14.do_fetch
-rw-rw-r-- 1 bitbake bitbake 4.4K Aug 17 11:39 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.22-r14.do_fetch.sigdata.5480624f2f674ebac9b4feea0e7fddd2
-rw-r--r-- 1 bitbake bitbake    0 Aug 17 11:40 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.22-r14.do_install
-rw-rw-r-- 1 bitbake bitbake  20K Aug 17 11:40 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.22-r14.do_install.sigdata.9e86640a966904c944ca4a9d2dbaf42d
-rw-r--r-- 1 bitbake bitbake    0 Aug 17 11:40 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.22-r14.do_package.qemux86-64
-rw-rw-r-- 1 bitbake bitbake 107K Aug 17 11:40 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.22-r14.do_package.sigdata.31c50dd6df72d7de49f20305431bde5a
-rw-r--r-- 1 bitbake bitbake    0 Aug 17 11:40 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.22-r14.do_package_write
-rw-r--r-- 1 bitbake bitbake    0 Aug 17 11:40 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.22-r14.do_package_write_ipk
-rw-rw-r-- 1 bitbake bitbake  12K Aug 17 11:40 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.22-r14.do_package_write_ipk.sigdata.08b8068d1171e21e7b0beb47968c62e9
-rw-r--r-- 1 bitbake bitbake    0 Aug 17 11:39 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.22-r14.do_patch
-rw-rw-r-- 1 bitbake bitbake 7.3K Aug 17 11:39 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.22-r14.do_patch.sigdata.763810d4ec77842b81c4c7fa53db89f2
-rw-r--r-- 1 bitbake bitbake    0 Aug 17 11:39 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.22-r14.do_populate_lic
-rw-rw-r-- 1 bitbake bitbake 8.4K Aug 17 11:39 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.22-r14.do_populate_lic.sigdata.d6ad83524f04119d257b7de9fdb8afe7
-rw-r--r-- 1 bitbake bitbake    0 Aug 17 11:40 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.22-r14.do_populate_sysroot.qemux86-64
-rw-rw-r-- 1 bitbake bitbake  21K Aug 17 11:40 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.22-r14.do_populate_sysroot.sigdata.80790beab090da0bd42f16d9721bb3da
-rw-r--r-- 1 bitbake bitbake    0 Aug 17 11:39 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.22-r14.do_unpack
-rw-rw-r-- 1 bitbake bitbake 2.4K Aug 17 11:39 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.22-r14.do_unpack.sigdata.d9e44d000aa0399b3ad8e25bcb27bdc0
-rw-r--r-- 1 bitbake bitbake    0 Aug 17 11:33 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.23-r0.do_build
-rw-r--r-- 1 bitbake bitbake    0 Aug 17 11:33 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.23-r0.do_compile
-rw-rw-r-- 1 bitbake bitbake  18K Aug 17 11:33 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.23-r0.do_compile.sigdata.8d9ab34ded1404b2be128be3e256ed8b
-rw-r--r-- 1 bitbake bitbake    0 Aug 17 11:32 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.23-r0.do_configure
-rw-rw-r-- 1 bitbake bitbake  23K Aug 17 11:32 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.23-r0.do_configure.sigdata.baf089614fe66512d9aedf3ce3618482
-rw-r--r-- 1 bitbake bitbake    0 Aug 17 11:31 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.23-r0.do_fetch
-rw-rw-r-- 1 bitbake bitbake 3.7K Aug 17 11:31 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.23-r0.do_fetch.sigdata.36c7fa53961686f5c07990bcde8d9c5e
-rw-r--r-- 1 bitbake bitbake    0 Aug 17 11:33 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.23-r0.do_install
-rw-rw-r-- 1 bitbake bitbake  20K Aug 17 11:33 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.23-r0.do_install.sigdata.c6a6448480f41fdc2611b2d49dc54e0e
-rw-r--r-- 1 bitbake bitbake    0 Aug 17 11:33 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.23-r0.do_package.qemux86-64
-rw-rw-r-- 1 bitbake bitbake 107K Aug 17 11:33 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.23-r0.do_package.sigdata.c1555fb8f7a9e84199f65bf65650b63b
-rw-r--r-- 1 bitbake bitbake    0 Aug 17 11:33 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.23-r0.do_package_write
-rw-r--r-- 1 bitbake bitbake    0 Aug 17 11:33 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.23-r0.do_package_write_ipk
-rw-rw-r-- 1 bitbake bitbake  12K Aug 17 11:33 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.23-r0.do_package_write_ipk.sigdata.e0e3df9bbb060b43487198d26eddb82f
-rw-r--r-- 1 bitbake bitbake    0 Aug 17 11:31 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.23-r0.do_patch
-rw-rw-r-- 1 bitbake bitbake 7.3K Aug 17 11:31 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.23-r0.do_patch.sigdata.85f190de6a4faae5cad7b4956f408b6b
-rw-r--r-- 1 bitbake bitbake    0 Aug 17 11:32 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.23-r0.do_populate_lic
-rw-rw-r-- 1 bitbake bitbake 8.4K Aug 17 11:32 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.23-r0.do_populate_lic.sigdata.0b1ec8929ab56acda421916477c51f3c
-rw-r--r-- 1 bitbake bitbake    0 Aug 17 11:33 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.23-r0.do_populate_sysroot.qemux86-64
-rw-rw-r-- 1 bitbake bitbake  21K Aug 17 11:33 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.23-r0.do_populate_sysroot.sigdata.68dd391c46bfc12987cb545fddd5eeca
-rw-r--r-- 1 bitbake bitbake    0 Aug 17 11:31 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.23-r0.do_unpack
-rw-rw-r-- 1 bitbake bitbake 2.1K Aug 17 11:31 tmp-eglibc/stamps/x86_64-oe-linux/binutils-cross-2.23-r0.do_unpack.sigdata.cdb642480037af2182aca8d2f0882547

OE qemux86-64@ ~/oe-core $ echo 'BINUVERSION_forcevariable = "2.23"' >> conf/local.conf
OE qemux86-64@ ~/oe-core $ bitbake -k binutils-cross | tee log.binutils
Parsing recipes...done.
Parsing of 831 .bb files complete (0 cached, 831 parsed). 1130 targets, 20 skipped, 0 masked, 0 errors.

Build Configuration:
BB_VERSION        = "1.15.3"
TARGET_ARCH       = "x86_64"
TARGET_OS         = "linux"
MACHINE           = "qemux86-64"
DISTRO_VERSION    = "oe-core.0"
TUNE_FEATURES     = "m64"
TARGET_FPU        = ""
meta              = "jansa/test:f1e2865d19226deabca0f402cebf5b92472f6073"
NOTE: Resolving any missing task queue dependencies
NOTE: Preparing runqueue
NOTE: Executing SetScene Tasks
NOTE: Executing RunQueue Tasks
NOTE: Tasks Summary: Attempted 82 tasks of which 82 didn't need to be rerun and all succeeded.

Just to test that 2.23 is preferred now:

OE qemux86-64@ ~/oe-core $ bitbake -c cleansstate -k binutils-cross | tee log.binutils
Loading cache...done.
Loaded 1131 entries from dependency cache.

Build Configuration:
BB_VERSION        = "1.15.3"
TARGET_ARCH       = "x86_64"
TARGET_OS         = "linux"
MACHINE           = "qemux86-64"
DISTRO_VERSION    = "oe-core.0"
TUNE_FEATURES     = "m64"
TARGET_FPU        = ""
meta              = "jansa/test:f1e2865d19226deabca0f402cebf5b92472f6073"

NOTE: Resolving any missing task queue dependencies
NOTE: Preparing runqueue
NOTE: Executing RunQueue Tasks
NOTE: Running task 1 of 2 (ID: 0, /OE/oe-core/openembedded-core/meta/recipes-devtools/binutils/binutils-cross_2.23.bb, do_clean)
NOTE: package binutils-cross-2.23-r0: task do_clean: Started
NOTE: package binutils-cross-2.23-r0: task do_clean: Succeeded
NOTE: Running task 2 of 2 (ID: 1, /OE/oe-core/openembedded-core/meta/recipes-devtools/binutils/binutils-cross_2.23.bb, do_cleansstate)
NOTE: package binutils-cross-2.23-r0: task do_cleansstate: Started
NOTE: package binutils-cross-2.23-r0: task do_cleansstate: Succeeded
NOTE: Tasks Summary: Attempted 2 tasks of which 0 didn't need to be rerun and all succeeded.