diff --git a/MD5 b/MD5
index afc4752..a2d3769 100644
--- a/MD5
+++ b/MD5
@@ -4,12 +4,12 @@ dc74f3941cd7eb5d5d2820a78e855291 *NEWS
 0090c3e305006e38f8ec8cef5616a3e2 *R/bayes.R
 1c95cfc1a6597466e42c386b0c6a6196 *R/extract.R
 c37085ee8b851dfd42eea66341904e82 *R/fit.R
-06b55a573555d6e0315478fb47fd48c0 *R/gcstats.R
+594c9ccd9c0816666791fb018756c2b2 *R/gcstats.R
 3ad97d0891d98e23cd5be6b4417067c5 *R/graphics.R
 79624c9cf668bfb2b05e8a339e98f393 *R/misc.R
 4b7f3320bad5b252cc0727ba9e019ab8 *R/model.R
 8ab48098af7628c6d2f155b8f9f24b74 *R/mutations.R
-1415cb2b3e892624fb7ea4ff76a2c46f *R/read.R
+574485fa2da5de558b74b117512a84a7 *R/read.R
 bfe91a98d0c94dab8ae8bcb554eb5acd *R/results.R
 f763a946f45e700642201c486263b969 *R/segments.R
 0359f75dbcc67975a0a8654cc04e32a3 *R/solutions.R
diff --git a/R/gcstats.R b/R/gcstats.R
index 9c7b0fa..c6a5e1b 100644
--- a/R/gcstats.R
+++ b/R/gcstats.R
@@ -22,7 +22,7 @@ gc.sample.stats <- function(file, col_types = "c--dd----d----",
         message("Collecting GC information ", appendLF = FALSE)
     }
     res <- chunk.apply(input = con, FUN = parse_chunck, col_types = col_types,
-        CH.MAX.SIZE = buffer, parallel = parallel)
+        CH.MAX.SIZE = buffer, CH.PARALLEL = parallel)
     close(con)
     if (verbose){
         message(" done\n")
diff --git a/R/read.R b/R/read.R
index 6de1968..11e120a 100644
--- a/R/read.R
+++ b/R/read.R
@@ -43,7 +43,7 @@ read.seqz.chr <- function(file, chr_name, col_names,
     }
     res <- chunk.apply(input = con, FUN = parse_chunck, chr_name = chr_name,
         col_names = col_names, col_types = col_types, CH.MAX.SIZE = buffer,
-        parallel = parallel)
+        CH.PARALLEL = parallel)
     close(con)
     res
 }
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..afd1914
--- /dev/null
+++ b/README.md
@@ -0,0 +1,11 @@
+Solve the following issues:
+<br>
+Collecting GC information Error in (function (x, col_types) : unused argument (parallel = 1)
+<br>
+Calls: main ... preprocess.seqz -> sequenza.extract -> gc.sample.stats -> chunk.apply
+<br>
+Execution halted
+
+The reason:
+<br>
+The "chunk.apply" function from R iotools package with new version does not have "parallel" parameter which has been changed to "CH.PARALLEL"