diff --git a/src/Parsers.jl b/src/Parsers.jl
index 22b093a5c..178d058ea 100644
--- a/src/Parsers.jl
+++ b/src/Parsers.jl
@@ -351,11 +351,12 @@ const unhex = Int8[
 function __init__()
     # FIXME Consider turing off `PCRE.UTF` in `Regex.compile_options`
     # https://github.com/JuliaLang/julia/pull/26731#issuecomment-380676770
-    resize!(empty!(status_line_regex),           Threads.nthreads())
-    resize!(empty!(request_line_regex),          Threads.nthreads())
-    resize!(empty!(header_field_regex),          Threads.nthreads())
-    resize!(empty!(obs_fold_header_field_regex), Threads.nthreads())
-    resize!(empty!(empty_header_field_regex),    Threads.nthreads())
+    nt = isdefined(Base.Threads, :maxthreadid) ? Threads.maxthreadid() : Threads.nthreads()
+    resize!(empty!(status_line_regex),           nt)
+    resize!(empty!(request_line_regex),          nt)
+    resize!(empty!(header_field_regex),          nt)
+    resize!(empty!(obs_fold_header_field_regex), nt)
+    resize!(empty!(empty_header_field_regex),    nt)
     return
 end
 
diff --git a/src/Servers.jl b/src/Servers.jl
index 3b804527a..df45fd907 100644
--- a/src/Servers.jl
+++ b/src/Servers.jl
@@ -363,7 +363,7 @@ Accepts new tcp connections and spawns async tasks to handle them."
 function listenloop(f, listener, conns, tcpisvalid,
                        max_connections, readtimeout, access_log, ready_to_accept, verbose)
     sem = Base.Semaphore(max_connections)
-    verbose >= 0 && @infov 1 "Listening on: $(listener.hostname):$(listener.hostport)"
+    verbose >= 0 && @infov 1 "Listening on: $(listener.hostname):$(listener.hostport), thread id: $(Threads.threadid())"
     notify(ready_to_accept)
     while isopen(listener)
         try
diff --git a/src/parsemultipart.jl b/src/parsemultipart.jl
index 2be1767c2..95ccce1ef 100644
--- a/src/parsemultipart.jl
+++ b/src/parsemultipart.jl
@@ -246,10 +246,11 @@ function parse_multipart_form(msg::Message)::Union{Vector{Multipart}, Nothing}
 end
 
 function __init__()
-    resize!(empty!(content_disposition_regex), Threads.nthreads())
-    resize!(empty!(content_disposition_flag_regex), Threads.nthreads())
-    resize!(empty!(content_disposition_pair_regex), Threads.nthreads())
-    resize!(empty!(content_type_regex), Threads.nthreads())
+    nt = isdefined(Base.Threads, :maxthreadid) ? Threads.maxthreadid() : Threads.nthreads()
+    resize!(empty!(content_disposition_regex), nt)
+    resize!(empty!(content_disposition_flag_regex), nt)
+    resize!(empty!(content_disposition_pair_regex), nt)
+    resize!(empty!(content_type_regex), nt)
     return
 end