diff --git a/src/buffers.jl b/src/buffers.jl
index 57d848d6c..156c76805 100644
--- a/src/buffers.jl
+++ b/src/buffers.jl
@@ -1,13 +1,23 @@
 MPIBuffertype{T} = Union{Ptr{T}, Array{T}, SubArray{T}, Ref{T}}
 MPIBuffertypeOrConst{T} = Union{MPIBuffertype{T}, SentinelPtr}
 
+# Implementation note
+# Base.cconvert and Base.unsafe_convert are a matched pair. 
+# We must implement Base.unsafe_convert(MPIPtr, ::typeof(Base.cconvert(MPIPtr, x))),
+# which is not possible to do generically. So we must define them as we find them.
+
 Base.cconvert(::Type{MPIPtr}, x::Union{Ptr{T}, Array{T}, Ref{T}}) where T = Base.cconvert(Ptr{T}, x)
 Base.cconvert(::Type{MPIPtr}, x::SubArray{T}) where T = Base.cconvert(Ptr{T}, x)
 function Base.unsafe_convert(::Type{MPIPtr}, x::MPIBuffertype{T}) where T
     ptr = Base.unsafe_convert(Ptr{T}, x)
     reinterpret(MPIPtr, ptr)
 end
-
+@static if VERSION >= v"1.14.0-DEV"
+    function Base.unsafe_convert(::Type{MPIPtr}, x::Base.OffsetCConvert{T}) where {T}
+        ptr = Base.unsafe_convert(Ptr{T}, x)   # Base handles offset arithmetic
+        reinterpret(MPIPtr, ptr)
+    end
+end
 
 Base.cconvert(::Type{MPIPtr}, x::String) = x
 Base.unsafe_convert(::Type{MPIPtr}, x::String) = reinterpret(MPIPtr, pointer(x))
diff --git a/test/runtests.jl b/test/runtests.jl
index 30d27b674..351c87564 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -84,7 +84,7 @@ testfiles = sort(filter(istest, readdir(testdir)))
                # test number of processes.
                "JULIA_MPI_TEST_NUM_PROCESSES"=>string(n))
     if f == "test_spawn.jl"
-        # Some command as the others, but always use a single process
+        # Same command as the others, but always use a single process
         run(cmd(1))
     elseif f == "test_threads.jl"
         # Legacy Intel MPI (before 2020) crashes threads tests: