diff --git a/src/Xpress.jl b/src/Xpress.jl
index bcd1ce42..1f0d45db 100644
--- a/src/Xpress.jl
+++ b/src/Xpress.jl
@@ -28,7 +28,6 @@ const libxprs = joinpath(
 include("Lib/Lib.jl")
 include("helper.jl")
 include("api.jl")
-include("xprs_callbacks.jl")
 include("license.jl")
 
 function initialize()
@@ -51,4 +50,6 @@ function __init__()
     return
 end
 
+export CallbackData
+
 end  # Xpress
diff --git a/src/helper.jl b/src/helper.jl
index 66d9bbb7..8c868e7e 100644
--- a/src/helper.jl
+++ b/src/helper.jl
@@ -290,3 +290,108 @@ const STOPSTATUS_STRING = Dict{Int,String}(
     Lib.XPRS_STOP_SOLLIMIT => "solution limit hit",
     Lib.XPRS_STOP_USER => "user interrupt.",
 )
+
+mutable struct CallbackData
+    model_root::XpressProblem
+    data::Any
+    model::XpressProblem
+end
+
+Base.broadcastable(x::CallbackData) = Ref(x)
+
+mutable struct _CallbackUserData
+    callback::Function
+    model::XpressProblem
+    data::Any
+end
+
+Base.cconvert(::Type{Ptr{Cvoid}}, x::_CallbackUserData) = x
+
+function Base.unsafe_convert(::Type{Ptr{Cvoid}}, x::_CallbackUserData)
+    return pointer_from_objref(x)::Ptr{Cvoid}
+end
+
+function _setcboptnode_wrapper(
+    ptr_inner::Lib.XPRSprob,
+    ptr_user_data::Ptr{Cvoid},
+    feas::Ptr{Cint},
+)
+    user_data = unsafe_pointer_to_objref(ptr_user_data)::_CallbackUserData
+    inner = XpressProblem(ptr_inner; finalize_env = false)
+    user_data.callback(CallbackData(user_data.model, user_data.data, inner))
+    return Cint(0)
+end
+
+function set_callback_optnode!(
+    model::XpressProblem,
+    callback::Function,
+    data::Any = nothing,
+)
+    callback_ptr = @cfunction(
+        _setcboptnode_wrapper,
+        Cint,
+        (Ptr{Cvoid}, Ptr{Cvoid}, Ptr{Cint})
+    )
+    user_data = _CallbackUserData(callback, model, data)
+    Lib.XPRSaddcboptnode(model.ptr, callback_ptr, user_data, 0)
+    return callback_ptr, user_data
+end
+
+function _setcbpreintsol_wrapper(
+    ptr_model::Lib.XPRSprob,
+    ptr_user_data::Ptr{Cvoid},
+    ::Ptr{Cint},
+    ::Ptr{Cint},
+    ::Ptr{Cdouble},
+)
+    user_data = unsafe_pointer_to_objref(ptr_user_data)::_CallbackUserData
+    inner = XpressProblem(ptr_model; finalize_env = false)
+    user_data.callback(CallbackData(user_data.model, user_data.data, inner))
+    return Cint(0)
+end
+
+function set_callback_preintsol!(
+    model::XpressProblem,
+    callback::Function,
+    data::Any = nothing,
+)
+    callback_ptr = @cfunction(
+        _setcbpreintsol_wrapper,
+        Cint,
+        (Ptr{Cvoid}, Ptr{Cvoid}, Ptr{Cint}, Ptr{Cint}, Ptr{Cdouble})
+    )
+    user_data = _CallbackUserData(callback, model, data)
+    Lib.XPRSaddcbpreintsol(model.ptr, callback_ptr, user_data, 0)
+    return callback_ptr, user_data
+end
+
+function _addcboutput2screen_wrapper(
+    ::Lib.XPRSprob,
+    ptr_user_data::Ptr{Cvoid},
+    msg::Ptr{Cchar},
+    ::Cint,
+    msgtype::Cint,
+)
+    user_data = unsafe_pointer_to_objref(ptr_user_data)::_CallbackUserData
+    if msgtype == 1 || (msgtype == 3 && user_data.data::Bool)
+        # Information || Warning
+        println(unsafe_string(msg))
+    elseif msgtype == 2 || msgtype == 4
+        # Not used || Error
+    else
+        # Exiting - buffers need flushing
+        flush(stdout)
+    end
+    return Cint(0)
+end
+
+function setoutputcb!(model::XpressProblem, show_warning::Bool)
+    callback_ptr = @cfunction(
+        _addcboutput2screen_wrapper,
+        Cint,
+        (Ptr{Cvoid}, Ptr{Cvoid}, Ptr{Cchar}, Cint, Cint)
+    )
+    user_data = _CallbackUserData(() -> nothing, model, show_warning)
+    Lib.XPRSaddcbmessage(model.ptr, callback_ptr, user_data, 0)
+    return callback_ptr, user_data
+end
diff --git a/src/xprs_callbacks.jl b/src/xprs_callbacks.jl
deleted file mode 100644
index 2d58e830..00000000
--- a/src/xprs_callbacks.jl
+++ /dev/null
@@ -1,132 +0,0 @@
-# Copyright (c) 2016: Joaquim Garcia, and contributors
-#
-# Use of this source code is governed by an MIT-style license that can be found
-# in the LICENSE.md file or at https://opensource.org/licenses/MIT.
-
-mutable struct CallbackData
-    model_root::XpressProblem # should not use operations here
-    data::Any # data for user
-    model::XpressProblem # local model # ptr_model::Ptr{Nothing}
-end
-Base.broadcastable(x::CallbackData) = Ref(x)
-
-# must be mutable
-mutable struct _CallbackUserData
-    callback::Function
-    model::XpressProblem
-    data::Any
-end
-Base.cconvert(::Type{Ptr{Cvoid}}, x::_CallbackUserData) = x
-function Base.unsafe_convert(::Type{Ptr{Cvoid}}, x::_CallbackUserData)
-    return pointer_from_objref(x)::Ptr{Cvoid}
-end
-
-export CallbackData
-
-function setcboptnode_wrapper(
-    ptr_model::Lib.XPRSprob,
-    my_object::Ptr{Cvoid},
-    feas::Ptr{Cint},
-)
-    usrdata = unsafe_pointer_to_objref(my_object)::_CallbackUserData
-    callback, model, data = usrdata.callback, usrdata.model, usrdata.data
-    model_inner = XpressProblem(ptr_model; finalize_env = false)
-    callback(CallbackData(model, data, model_inner))
-    return zero(Cint)
-end
-
-function set_callback_optnode!(
-    model::XpressProblem,
-    callback::Function,
-    data::Any = nothing,
-)
-    callback_ptr = @cfunction(
-        setcboptnode_wrapper,
-        Cint,
-        (Ptr{Cvoid}, Ptr{Cvoid}, Ptr{Cint})
-    )
-    usrdata = _CallbackUserData(callback, model, data)
-    Lib.XPRSaddcboptnode(model.ptr, callback_ptr, usrdata, 0)
-    # we need to keep a reference to the callback function
-    # so that it isn't garbage collected
-    return callback_ptr, usrdata
-end
-
-function setcbpreintsol_wrapper(
-    ptr_model::Lib.XPRSprob,
-    my_object::Ptr{Cvoid},
-    soltype::Ptr{Cint},
-    ifreject::Ptr{Cint},
-    cutoff::Ptr{Cdouble},
-)
-    usrdata = unsafe_pointer_to_objref(my_object)::_CallbackUserData
-    callback, model, data = usrdata.callback, usrdata.model, usrdata.data
-    model_inner = XpressProblem(ptr_model; finalize_env = false)
-    callback(CallbackData(model, data, model_inner))
-    return zero(Cint)
-end
-
-function set_callback_preintsol!(
-    model::XpressProblem,
-    callback::Function,
-    data::Any = nothing,
-)
-    callback_ptr = @cfunction(
-        setcbpreintsol_wrapper,
-        Cint,
-        (Ptr{Cvoid}, Ptr{Cvoid}, Ptr{Cint}, Ptr{Cint}, Ptr{Cdouble})
-    )
-    usrdata = _CallbackUserData(callback, model, data)
-    Lib.XPRSaddcbpreintsol(model.ptr, callback_ptr, usrdata, 0)
-    # we need to keep a reference to the callback function
-    # so that it isn't garbage collected
-    return callback_ptr, usrdata
-end
-
-function addcboutput2screen_wrapper(
-    ptr_model::Lib.XPRSprob,
-    my_object::Ptr{Cvoid},
-    msg::Ptr{Cchar},
-    len::Cint,
-    msgtype::Cint,
-)
-    usrdata = unsafe_pointer_to_objref(my_object)::_CallbackUserData
-    show_warning = usrdata.data::Bool
-
-    if msgtype == 4
-        #= Error =#
-        return zero(Cint)
-    elseif msgtype == 3 && show_warning
-        #= Warning =#
-        msg_str = unsafe_string(msg)
-        println(msg_str)
-        return zero(Cint)
-    elseif msgtype == 2
-        #= Not used =#
-        return zero(Cint)
-    elseif msgtype == 1
-        #= Information =#
-        msg_str = unsafe_string(msg)
-        println(msg_str)
-        return zero(Cint)
-    else
-        #= Exiting - buffers need flushing  =#
-        flush(stdout)
-        return zero(Cint)
-    end
-end
-
-function setoutputcb!(model::XpressProblem, show_warning::Bool)
-    callback_ptr = @cfunction(
-        addcboutput2screen_wrapper,
-        Cint,
-        (Ptr{Cvoid}, Ptr{Cvoid}, Ptr{Cchar}, Cint, Cint)
-    )
-    usrdata = _CallbackUserData(_null, model, show_warning)
-    Lib.XPRSaddcbmessage(model.ptr, callback_ptr, usrdata, 0)
-    return callback_ptr, usrdata
-end
-
-function _null()
-    return
-end