diff --git a/cliutils.nimble b/cliutils.nimble
index 992e056..d0b91b3 100644
--- a/cliutils.nimble
+++ b/cliutils.nimble
@@ -1,10 +1,10 @@
 # Package
 
-version       = "0.6.5"
+version       = "0.7.0"
 author        = "Jonathan Bernard"
 description   = "Helper functions for writing command line interfaces."
 license       = "MIT"
 
 # Dependencies
 
-requires @["nim >= 0.19.0", "docopt >= 0.6.8"]
+requires @["nim >= 1.6.0", "docopt >= 0.6.8"]
diff --git a/cliutilspkg/procutil.nim b/cliutilspkg/procutil.nim
index 12664b0..e269088 100644
--- a/cliutilspkg/procutil.nim
+++ b/cliutilspkg/procutil.nim
@@ -1,21 +1,20 @@
-import osproc, sequtils, streams, strtabs
+import osproc, streams, strtabs, strutils
 
 ## Process execution
-type HandleProcMsgCB* = proc (outMsg: TaintedString,
-                              errMsg: TaintedString, cmd: string): void
+type HandleProcMsgCB* = proc (outMsg: string, errMsg: string, cmd: string): void
 
-proc sendMsg*(h: HandleProcMsgCB, outMsg: TaintedString,
-              errMsg: TaintedString = "", cmd: string = ""): void =
+proc sendMsg*(h: HandleProcMsgCB, outMsg: string,
+              errMsg: string = "", cmd: string = ""): void =
   if h != nil: h(outMsg, errMsg, cmd)
 
 proc makeProcMsgHandler*(outSink, errSink: File, prefixCmd: bool = true): HandleProcMsgCB =
-  result = proc(outMsg, errMsg: TaintedString, cmd: string): void {.closure.} =
+  result = proc(outMsg, errMsg: string, cmd: string): void {.closure.} =
     let prefix = if cmd.len == 0 or not prefixCmd: "" else: cmd & ": "
     if outMsg.len > 0: outSink.writeLine(prefix & outMsg)
     if errMsg.len > 0: errSink.writeLine(prefix & errMsg)
 
 proc makeProcMsgHandler*(outSink, errSink: Stream, prefixCmd: bool = true): HandleProcMsgCB =
-  result = proc(outMsg, errMsg: TaintedString, cmd: string): void {.closure.} =
+  result = proc(outMsg, errMsg: string, cmd: string): void {.closure.} =
     let prefix = if cmd.len == 0 or not prefixCmd: "" else: cmd & ": "
     if outMsg.len > 0: outSink.writeLine(prefix & outMsg)
     if errMsg.len > 0: errSink.writeLine(prefix & errMsg)
@@ -24,7 +23,7 @@ proc combineProcMsgHandlers*(a, b: HandleProcMsgCB): HandleProcMsgCB =
   if a == nil: result = b
   elif b == nil: result = a
   else:
-    result = proc(cmd: string, outMsg, errMsg: TaintedString): void =
+    result = proc(cmd: string, outMsg, errMsg: string): void =
       a(cmd, outMsg, errMsg)
       b(cmd, outMsg, errMsg)
 
@@ -33,7 +32,7 @@ proc waitFor*(p: Process, msgCB: HandleProcMsgCB, procCmd: string = ""): int =
   var pout = outputStream(p)
   var perr = errorStream(p)
 
-  var line = newStringOfCap(120).TaintedString
+  var line = newStringOfCap(120)
   while true:
     if pout.readLine(line):
       msgCB.sendMsg(line, "", procCmd)
@@ -57,13 +56,13 @@ proc execWithOutput*(command: string, workingDir:string = "",
            args: openArray[string] = [], env: StringTableRef = nil,
            options: set[ProcessOption] = {poUsePath},
            msgCB: HandleProcMsgCB = nil):
-    tuple[output, error: TaintedString, exitCode: int] =
+    tuple[output, error: string, exitCode: int] =
 
-  result = (TaintedString"", TaintedString"", -1)
-  var outSeq, errSeq: seq[TaintedString]
+  result = ("", "", -1)
+  var outSeq, errSeq: seq[string]
   outSeq = @[]; errSeq = @[]
   let outputCollector = combineProcMsgHandlers(msgCB,
-    proc(outMsg, errMsg: TaintedString, cmd: string): void {.closure.} =
+    proc(outMsg, errMsg: string, cmd: string): void {.closure.} =
       if outMsg.len > 0: outSeq.add(outMsg)
       if errMsg.len > 0: errSeq.add(errMsg))