Dear all, I follow the official step (https://github.com/seL4/refos-manifest) to build RefOS and it occurs the following error message. In file included from /home/chi-wai/Workspaces/microkernel/RefOS/libs/librefos/src/sync.c:16:0: ~/Workspaces/RefOS/stage/arm/imx31/include/refos/refos.h:73:1: *error: unknown type name ‘uint32_t’* ~/Workspaces/RefOS/stage/arm/imx31/include/refos/refos.h:73:23: *error: unknown type name ‘uint32_t’* In file included from /home/chi-wai/Workspaces/microkernel/RefOS/libs/librefos/src/sync.c:18:0: ~/Workspaces/RefOS/stage/arm/imx31/include/refos-util/cspace.h:44:72: *error: unknown type name ‘uint32_t’* ~/Workspaces/RefOS/libs/librefos/src/sync.c: In function ‘sync_create_mutex’: ~/Workspaces/RefOS/libs/librefos/src/sync.c:49:5: *warning*: ‘seL4_Notify’ is deprecated (declared at /home/chi-wai/Workspaces/microkernel/RefOS/stage/arm/imx31/include/sel4/deprecated.h:23): use seL4_Signal [-Wdeprecated-declarations] ~/Workspaces/RefOS/libs/librefos/src/sync.c: In function ‘sync_acquire’: ~/Workspaces/RefOS/libs/librefos/src/sync.c:65:5: *error: invalid initializer* ~/Workspaces/RefOS/libs/librefos/src/sync.c: In function ‘sync_release’: ~/Workspaces/RefOS/libs/librefos/src/sync.c:74:5: *warning*: ‘seL4_Notify’ is deprecated (declared at /home/chi-wai/Workspaces/microkernel/RefOS/stage/arm/imx31/include/sel4/deprecated.h:23): use seL4_Signal [-Wdeprecated-declarations] make[1]: *** [src/sync.o] Error 1 make: *** [librefos] Error 2 Does RefOS use the old seL4 API ? If it is, which version I need to downgrade? Thanks for any help or suggestion, Gapry. https://gapry.wordpress.com/