diff --git a/.travis.yml b/.travis.yml
index 4fb6e09..3deb3f1 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -3,8 +3,7 @@ os:
     - osx
     - linux
 julia:
-    - 1.3
-    - 1.4
+    - 1.5
     - nightly
 matrix:
   allow_failures:
diff --git a/Project.toml b/Project.toml
index 20959c0..7468f04 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,7 +1,7 @@
 name = "Sundials"
 uuid = "c3572dad-4567-51f8-b174-8c6c989267f4"
 authors = ["Chris Rackauckas <accounts@chrisrackauckas.com>"]
-version = "4.2.6"
+version = "4.3.0"
 
 [deps]
 CEnum = "fa961155-64e5-5f13-b03f-caf6b980ea82"
@@ -16,11 +16,11 @@ Sundials_jll = "fb77eaff-e24c-56d4-86b1-d163f2edb164"
 
 [compat]
 CEnum = "0.2, 0.3, 0.4"
-DataStructures = "0.17.0, 0.18"
-DiffEqBase = "6.21"
+DataStructures = "0.18"
+DiffEqBase = "6.44"
 Reexport = "0.2"
 Sundials_jll = "5.2"
-julia = "1.3"
+julia = "1"
 
 [extras]
 DiffEqOperators = "9fdde737-9c7f-55bf-ade8-46b3f136cc48"
diff --git a/src/common_interface/integrator_types.jl b/src/common_interface/integrator_types.jl
index 5d6408d..afe14c7 100644
--- a/src/common_interface/integrator_types.jl
+++ b/src/common_interface/integrator_types.jl
@@ -155,8 +155,9 @@ DiffEqBase.postamble!(integrator::AbstractSundialsIntegrator) = nothing
 
 @inline function DiffEqBase.step!(integrator::AbstractSundialsIntegrator)
   if integrator.opts.advance_to_tstop
-    while integrator.tdir*(integrator.t-DataStructures.top(integrator.opts.tstops)) < -1e6eps()
-        tstop = DataStructures.top(integrator.opts.tstops)
+    # The call to first is an overload of Base.first implemented in DataStructures
+    while integrator.tdir*(integrator.t-first(integrator.opts.tstops)) < -1e6eps()
+        tstop = first(integrator.opts.tstops)
         set_stop_time(integrator,tstop)
         integrator.tprev = integrator.t
         if !(typeof(integrator.opts.callback.continuous_callbacks)<:Tuple{})
@@ -174,7 +175,7 @@ DiffEqBase.postamble!(integrator::AbstractSundialsIntegrator) = nothing
           integrator.uprev .= integrator.u
       end
       if !isempty(integrator.opts.tstops)
-          tstop = DataStructures.top(integrator.opts.tstops)
+          tstop = first(integrator.opts.tstops)
           set_stop_time(integrator,tstop)
           solver_step(integrator,tstop)
       else
diff --git a/src/common_interface/integrator_utils.jl b/src/common_interface/integrator_utils.jl
index 5b93d98..c8561ea 100644
--- a/src/common_interface/integrator_utils.jl
+++ b/src/common_interface/integrator_utils.jl
@@ -38,8 +38,9 @@ function DiffEqBase.savevalues!(integrator::AbstractSundialsIntegrator,force_sav
   saved, savedexactly = false, false
   !integrator.opts.save_on && return saved, savedexactly
   uType = eltype(integrator.sol.u)
+  # The call to first is an overload of Base.first implemented in DataStructures
   while !isempty(integrator.opts.saveat) &&
-    integrator.tdir*DataStructures.top(integrator.opts.saveat) < integrator.tdir*integrator.t
+    integrator.tdir*first(integrator.opts.saveat) < integrator.tdir*integrator.t
     saved = true
     curt = pop!(integrator.opts.saveat)
 
diff --git a/src/common_interface/solve.jl b/src/common_interface/solve.jl
index b4b3169..69ed5c1 100644
--- a/src/common_interface/solve.jl
+++ b/src/common_interface/solve.jl
@@ -1153,8 +1153,9 @@ function DiffEqBase.solve!(integrator::AbstractSundialsIntegrator)
     while !isempty(integrator.opts.tstops)
         # Sundials can have floating point issues approaching a tstop if
         # there is a modifying event each
-        while integrator.tdir*(integrator.t-DataStructures.top(integrator.opts.tstops)) < -1e6eps()
-            tstop = DataStructures.top(integrator.opts.tstops)
+        # The call to first is an overload of Base.first implemented in DataStructures
+        while integrator.tdir*(integrator.t-first(integrator.opts.tstops)) < -1e6eps()
+            tstop = first(integrator.opts.tstops)
             set_stop_time(integrator,tstop)
             integrator.tprev = integrator.t
             if !(typeof(integrator.opts.callback.continuous_callbacks)<:Tuple{})
@@ -1217,7 +1218,7 @@ end
 function handle_tstop!(integrator::AbstractSundialsIntegrator)
     tstops = integrator.opts.tstops
     if !isempty(tstops)
-      if integrator.tdir*(integrator.t-DataStructures.top(integrator.opts.tstops)) > -1e6eps()
+      if integrator.tdir*(integrator.t-first(integrator.opts.tstops)) > -1e6eps()
           pop!(tstops)
           t = integrator.t
           integrator.just_hit_tstop = true