diff --git a/.travis.yml b/.travis.yml
index 8084d03..84efbbf 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -7,6 +7,7 @@ julia:
   - 1.0
   - 1.1
   - 1.2
+  - 1.3
   - nightly
 notifications:
   email: true
diff --git a/src/sos_sdps.jl b/src/sos_sdps.jl
index 3037e00..a7af726 100644
--- a/src/sos_sdps.jl
+++ b/src/sos_sdps.jl
@@ -147,7 +147,7 @@ function reconstruct(Ps::Vector{M},
     tmp = [zeros(Float64, size(first(transfP))) for _ in 1:lU]
 
     Threads.@threads for π in 1:lU
-        tmp[π] = perm_avg(tmp[π], transfP[π], values(preps))
+        tmp[π] = perm_avg!(tmp[π], transfP[π], values(preps))
     end
 
     recP = sum(tmp)./length(preps)
@@ -155,7 +155,7 @@ function reconstruct(Ps::Vector{M},
     return recP
 end
 
-function perm_avg(result, P, perms)
+function perm_avg!(result, P, perms)
     lp = length(first(perms).d)
     for p in perms
         # result .+= view(P, p.d, p.d)