diff --git a/.travis.yml b/.travis.yml
index 8fb76e5050..40d5937c02 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,5 +1,5 @@
 os: linux
-dist: xenial
+dist: bionic
 
 language: python
 # our build matrix
diff --git a/nipype/algorithms/misc.py b/nipype/algorithms/misc.py
index 756cdb8a10..50ae18f5be 100644
--- a/nipype/algorithms/misc.py
+++ b/nipype/algorithms/misc.py
@@ -1408,7 +1408,7 @@ def merge_rois(in_files, in_idxs, in_ref, dtype=None, out_file=None):
     # to avoid memory errors
     if op.splitext(in_ref)[1] == ".gz":
         try:
-            iflogger.info("uncompress %i", in_ref)
+            iflogger.info("uncompress %s", in_ref)
             sp.check_call(["gunzip", in_ref], stdout=sp.PIPE, shell=True)
             in_ref = op.splitext(in_ref)[0]
         except: