diff --git a/src/HTTP.jl b/src/HTTP.jl
index 012c90107..04b96b2bd 100644
--- a/src/HTTP.jl
+++ b/src/HTTP.jl
@@ -31,6 +31,11 @@ if !isdefined(Base, :pairs)
     pairs(x) = x
 end
 
+if !isdefined(Base, :Nothing)
+    const Nothing = Void
+    const Cvoid = Void
+end
+
 if VERSION < v"0.7.0-DEV.2575"
     const Dates = Base.Dates
 else
diff --git a/src/handlers.jl b/src/handlers.jl
index b7f09b019..33173d194 100644
--- a/src/handlers.jl
+++ b/src/handlers.jl
@@ -1,5 +1,10 @@
 module Handlers
 
+if !isdefined(Base, :Nothing)
+    const Nothing = Void
+    const Cvoid = Void
+end
+
 function val(v)
     @static if VERSION < v"0.7.0-DEV.1395"
         Val{v}()
@@ -59,7 +64,7 @@ struct Router <: Handler
     segments::Dict{String, Val}
     sym::Symbol
     func::Function
-    function Router(ff::Union{Handler, Function, Void}=nothing)
+    function Router(ff::Union{Handler, Function, Nothing}=nothing)
         sym = gensym()
         if ff == nothing
             f = @eval $sym(args...) = FourOhFour
diff --git a/src/parser.jl b/src/parser.jl
index 55cac9aca..f5cf01fd8 100644
--- a/src/parser.jl
+++ b/src/parser.jl
@@ -834,8 +834,8 @@ function parse!(r, parser, bytes, len, lenient, host, method, maxuri, maxheader,
                     limit = min(limit, maxheader)
                     ptr = pointer(bytes, p)
                     @debug(PARSING_DEBUG, Base.escape_string(string('\'', Char(bytes[p]), '\'')))
-                    p_cr = ccall(:memchr, Ptr{Void}, (Ptr{Void}, Cint, Csize_t), ptr, CR, limit)
-                    p_lf = ccall(:memchr, Ptr{Void}, (Ptr{Void}, Cint, Csize_t), ptr, LF, limit)
+                    p_cr = ccall(:memchr, Ptr{Cvoid}, (Ptr{Cvoid}, Cint, Csize_t), ptr, CR, limit)
+                    p_lf = ccall(:memchr, Ptr{Cvoid}, (Ptr{Cvoid}, Cint, Csize_t), ptr, LF, limit)
                     @debug(PARSING_DEBUG, limit)
                     @debug(PARSING_DEBUG, Int(p_cr))
                     @debug(PARSING_DEBUG, Int(p_lf))
diff --git a/src/precompile.jl b/src/precompile.jl
index 165b2c3e9..4caf645e6 100644
--- a/src/precompile.jl
+++ b/src/precompile.jl
@@ -44,7 +44,7 @@ function _precompile_()
     @assert precompile(HTTP.ignorewhitespace, (Array{UInt8, 1}, Int64, Int64,))
     @assert precompile(HTTP.Cookies.String, (HTTP.Cookies.Cookie, Bool,))
     @assert precompile(HTTP.Cookies.shouldsend, (HTTP.Cookies.Cookie, Bool, String, String,))
-    @assert precompile(HTTP.Client, (Void, HTTP.RequestOptions,))
+    @assert precompile(HTTP.Client, (Nothing, HTTP.RequestOptions,))
     @assert precompile(HTTP.Cookies.parsecookievalue, (Base.SubString{String}, Bool,))
     @assert precompile(HTTP.ignorewhitespace, (Array{UInt8, 1}, UInt64, Int64,))
     @assert precompile(HTTP.Cookies.hash, (HTTP.Cookies.Cookie, UInt,))
diff --git a/src/server.jl b/src/server.jl
index 449e3cb36..6ae0b8458 100644
--- a/src/server.jl
+++ b/src/server.jl
@@ -1,5 +1,10 @@
 module Nitrogen
 
+if !isdefined(Base, :Nothing)
+    const Nothing = Void
+    const Cvoid = Void
+end
+
 if VERSION < v"0.7.0-DEV.2575"
     const Dates = Base.Dates
 else
@@ -47,7 +52,7 @@ mutable struct ServerOptions
     maxheader::Int64
     maxbody::Int64
     support100continue::Bool
-    chunksize::Union{Void, Int}
+    chunksize::Union{Nothing, Int}
     logbody::Bool
 end
 
@@ -58,7 +63,7 @@ ServerOptions(; tlsconfig::HTTP.TLS.SSLConfig=HTTP.TLS.SSLConfig(true),
                 maxheader::Int64=HTTP.DEFAULT_MAX_HEADER,
                 maxbody::Int64=HTTP.DEFAULT_MAX_BODY,
                 support100continue::Bool=true,
-                chunksize::Union{Void, Int}=nothing,
+                chunksize::Union{Nothing, Int}=nothing,
                 logbody::Bool=true) =
     ServerOptions(tlsconfig, readtimeout, ratelimit, maxbody, maxuri, maxheader, support100continue, chunksize, logbody)
 
diff --git a/src/types.jl b/src/types.jl
index 80da22676..8a41fd81c 100644
--- a/src/types.jl
+++ b/src/types.jl
@@ -12,8 +12,8 @@ schemetype(::Type{TLS.SSLContext}) = https
 
 const Headers = Dict{String, String}
 
-const Option{T} = Union{T, Void}
-not(::Void) = true
+const Option{T} = Union{T, Nothing}
+not(::Nothing) = true
 not(x) = false
 function get(value::T, name::Symbol, default::R)::R where {T, R}
     val = getfield(value, name)::Option{R}
@@ -220,7 +220,7 @@ mutable struct Response
     cookies::Vector{Cookie}
     headers::Headers
     body::FIFOBuffer
-    request::Union{Void,Request}
+    request::Union{Nothing,Request}
     history::Vector{Response}
 end
 
@@ -247,7 +247,7 @@ Response(; status::Int=200,
          cookies::Vector{Cookie}=Cookie[],
          headers::Headers=Headers(),
          body::FIFOBuffer=FIFOBuffer(""),
-         request::Union{Void,Request}=nothing,
+         request::Union{Nothing,Request}=nothing,
          history::Vector{Response}=Response[]) =
     Response(status, Int16(1), Int16(1), cookies, headers, body, request, history)