Update ujit.md

doc/ujit.md

@@ -2,9 +2,11 @@ MicroJIT (uJIT)
 ===============
 
 MicroJIT is a lightweight, minimalistic Ruby JIT built inside the CRuby/MRI binary.
-It lazily compiles code using a Basic Block Versioning (BBV) architecture and generates x86-64 code. The target use case is that of servers running
-Ruby on Rails, an area where CRuby's MJIT has not yet managed to deliver speedups. We currently support only MacOS and Linux at this stage. This
-project is open source and falls under the same license as CRuby.
+It lazily compiles code using a Basic Block Versioning (BBV) architecture. The target use case is that of servers running
+Ruby on Rails, an area where CRuby's MJIT has not yet managed to deliver speedups. 
+To simplify development, we currently support only MacOS and Linux on x86-64, but an ARM64 backend
+is part of future plans.
+This project is open source and falls under the same license as CRuby.
 
 ## Installation