diff --git a/src/Encoding.h b/src/Encoding.h
index 297650c847..b097d7f44b 100644
--- a/src/Encoding.h
+++ b/src/Encoding.h
@@ -14,7 +14,6 @@
 #define ENCODING_H
 
 #include "support/docstring.h"
-#include "support/trivstring.h"
 #include "support/types.h"
 
 #include <map>
diff --git a/src/Language.h b/src/Language.h
index ddd6edf7c2..56e324a359 100644
--- a/src/Language.h
+++ b/src/Language.h
@@ -16,7 +16,6 @@
 #define LANGUAGE_H
 
 #include "support/docstring.h"
-#include "support/trivstring.h"
 
 #include <map>
 #include <set>
diff --git a/src/support/Makefile.am b/src/support/Makefile.am
index 2122cc4a42..4ff0ebd2cb 100644
--- a/src/support/Makefile.am
+++ b/src/support/Makefile.am
@@ -115,8 +115,6 @@ liblyxsupport_a_SOURCES = \
 	Translator.h \
 	Timeout.cpp \
 	Timeout.h \
-	trivstring.cpp \
-	trivstring.h \
 	types.h \
 	unique_ptr.h \
 	userinfo.cpp \
diff --git a/src/support/docstring.h b/src/support/docstring.h
index 2a760eacee..40806e1f40 100644
--- a/src/support/docstring.h
+++ b/src/support/docstring.h
@@ -65,14 +65,11 @@ std::string const & empty_string();
 // defined in docstring.cpp
 bool operator==(docstring const &, char const *);
 
-#ifdef STD_STRING_USES_COW
-template<typename Char> class trivial_string;
-typedef trivial_string<char> trivstring;
-typedef trivial_string<char_type> trivdocstring;
-#else
+//trivstring signalizes thread-safety request; should not be needed for any
+//C++11 conformant std::basic_string, e.g. GCC >= 5.
+//Once properly tested we can ditch these two in favour of std::string/docstring.
 typedef std::string trivstring;
 typedef docstring trivdocstring;
-#endif
 
 } // namespace lyx
 
diff --git a/src/support/tests/check_trivstring.cpp b/src/support/tests/check_trivstring.cpp
index 1b604657f4..844164510d 100644
--- a/src/support/tests/check_trivstring.cpp
+++ b/src/support/tests/check_trivstring.cpp
@@ -1,6 +1,5 @@
 #include <config.h>
 
-#include "../trivstring.h"
 #include "../docstring.h"
 
 #include <iostream>
diff --git a/src/support/trivstring.cpp b/src/support/trivstring.cpp
deleted file mode 100644
index c5102526a8..0000000000
--- a/src/support/trivstring.cpp
+++ /dev/null
@@ -1,261 +0,0 @@
-/**
- * \file trivstring.cpp
- * This file is part of LyX, the document processor.
- * Licence details can be found in the file COPYING.
- *
- * \author Georg Baum
- *
- * Full author contact details are available in file CREDITS.
- */
-
-#include <config.h>
-
-#include "support/trivstring.h"
-#include "support/docstring.h"
-
-#ifdef STD_STRING_USES_COW
-#include <algorithm>
-#include <stdexcept>
-
-using namespace std;
-
-namespace lyx {
-
-template trivial_string<char>::trivial_string(trivial_string const &);
-template trivial_string<char_type>::trivial_string(trivial_string const &);
-template<typename Char>
-trivial_string<Char>::trivial_string(trivial_string const & that) : size_(that.size_)
-{
-	if (use_sso())
-		copy(that.data_sso(), that.data_sso() + size_ + 1, data_sso());
-	else if (size_ > 0) {
-		data_ = new Char[size_ + 1];
-		copy(that.data_, that.data_ + size_ + 1, data_);
-	} else {
-		// Happens only for really big Char types
-		data_ = 0;
-	}
-}
-
-
-template<typename Char>
-trivial_string<Char>::trivial_string(Char const * that, size_t n) : size_(n)
-{
-	if (use_sso()) {
-		copy(that, that + size_, data_sso());
-		data_sso()[size_] = '\0';
-	} else if (size_ > 0) {
-		data_ = new Char[size_ + 1];
-		copy(that, that + size_, data_);
-		data_[size_] = '\0';
-	} else {
-		// Happens only for really big Char types
-		data_ = 0;
-	}
-}
-
-
-template trivial_string<char>::trivial_string(string const &);
-template trivial_string<char_type>::trivial_string(docstring const &);
-template<typename Char>
-trivial_string<Char>::trivial_string(_stdstring const & that)
-	: size_(that.length())
-{
-	if (use_sso()) {
-		copy(that.begin(), that.end(), data_sso());
-		data_sso()[size_] = '\0';
-	} else if (size_ > 0) {
-		data_ = new Char[size_ + 1];
-		copy(that.begin(), that.end(), data_);
-		data_[size_] = '\0';
-	} else {
-		// Happens only for really big Char types
-		data_ = 0;
-	}
-}
-
-
-template trivial_string<char> &
-trivial_string<char>::operator=(trivial_string const &);
-template trivial_string<char_type> &
-trivial_string<char_type>::operator=(trivial_string const &);
-template<typename Char>
-trivial_string<Char> & trivial_string<Char>::operator=(trivial_string const & that)
-{
-	if (&that == this)
-		return *this;
-	if (!use_sso())
-		delete[] data_;
-	size_ = that.size_;
-	if (use_sso())
-		copy(that.data_sso(), that.data_sso() + size_ + 1, data_sso());
-	else if (size_ > 0) {
-		data_ = new Char[size_ + 1];
-		copy(that.data_, that.data_ + size_ + 1, data_);
-	} else {
-		// Happens only for really big Char types
-		data_ = 0;
-	}
-	return *this;
-}
-
-
-template trivial_string<char> &
-trivial_string<char>::operator=(string const &);
-template trivial_string<char_type> &
-trivial_string<char_type>::operator=(docstring const &);
-template<typename Char>
-trivial_string<Char> &
-trivial_string<Char>::operator=(_stdstring const & that)
-{
-	if (!use_sso())
-		delete[] data_;
-	size_ = that.size();
-	if (use_sso()) {
-		copy(that.begin(), that.end(), data_sso());
-		data_sso()[size_] = '\0';
-	} else if (size_ > 0) {
-		data_ = new Char[size_ + 1];
-		copy(that.begin(), that.end(), data_);
-	} else {
-		// Happens only for really big Char types
-		data_ = 0;
-	}
-	return *this;
-}
-
-
-template void
-trivial_string<char>::swap(trivial_string<char> &);
-template void
-trivial_string<char_type>::swap(trivial_string<char_type> &);
-template<typename Char>
-void trivial_string<Char>::swap(trivial_string & that)
-{
-	size_t const sizetmp = that.size_;
-	that.size_ = size_;
-	size_ = sizetmp;
-	Char * const datatmp = that.data_;
-	that.data_ = data_;
-	data_ = datatmp;
-}
-
-
-template<typename Char>
-int trivial_string<Char>::compare(trivial_string const & other) const
-{
-	size_t const lsize = this->length();
-	size_t const rsize = other.length();
-	size_t const len = min(lsize, rsize);
-	int r = char_traits<Char>::compare(c_str(), other.c_str(), len);
-	if (r == 0) {
-		if (lsize > rsize)
-			r = 1;
-		else if (lsize < rsize)
-			r = -1;
-	}
-	return r;
-}
-
-
-template trivial_string<char> trivial_string<char>::substr(size_t, size_t) const;
-template trivial_string<char_type> trivial_string<char_type>::substr(size_t, size_t) const;
-template<typename Char>
-trivial_string<Char> trivial_string<Char>::substr(size_t pos, size_t n) const
-{
-	if (pos > length())
-		throw out_of_range("trivial_string::substr");
-	if (n == _stdstring::npos)
-		n = length() - pos;
-	size_t const l = min(pos + n, length());
-	return trivial_string(c_str() + pos, l - pos);
-}
-
-
-template trivial_string<char>::operator string() const;
-template trivial_string<char_type>::operator docstring() const;
-template<typename Char>
-trivial_string<Char>::operator _stdstring() const
-{
-	if (use_sso())
-		return _stdstring(data_sso(), size_);
-	if (size_ > 0)
-		return _stdstring(data_, size_);
-	// Happens only for really big Char types
-	return _stdstring();
-}
-
-
-template char const * trivial_string<char>::c_str() const;
-template char_type const * trivial_string<char_type>::c_str() const;
-template<typename Char> Char const * trivial_string<Char>::c_str() const
-{
-	if (use_sso())
-		return data_sso();
-	if (size_ > 0)
-		return data_;
-	// Happens only for really big Char types
-	static const Char empty_char = '\0';
-	return &empty_char;
-}
-
-
-template char trivial_string<char>::operator[](size_t) const;
-template char_type trivial_string<char_type>::operator[](size_t) const;
-template <typename Char> Char trivial_string<Char>::operator[](size_t i) const
-{
-	return c_str()[i];
-}
-
-
-template bool operator<(trivial_string<char> const &,
-                        trivial_string<char> const &);
-template bool operator<(trivial_string<char_type> const &,
-                        trivial_string<char_type> const &);
-template <typename Char>
-bool operator<(trivial_string<Char> const & lhs, trivial_string<Char> const & rhs)
-{
-	return lhs.compare(rhs) < 0;
-}
-
-
-template bool operator==(trivial_string<char> const &,
-                         trivial_string<char> const &);
-template bool operator==(trivial_string<char_type> const &,
-                         trivial_string<char_type> const &);
-template <typename Char>
-bool operator==(trivial_string<Char> const & lhs, trivial_string<Char> const & rhs)
-{
-	return lhs.compare(rhs) == 0;
-}
-
-
-template bool operator==(trivial_string<char> const &, char const *);
-template bool operator==(trivial_string<char_type> const &, char_type const *);
-template <typename Char>
-bool operator==(trivial_string<Char> const & lhs, Char const * rhs)
-{
-	return lhs.compare(trivial_string<Char>(rhs)) == 0;
-}
-
-
-template bool operator==(char const *, trivial_string<char> const &);
-template bool operator==(char_type const *, trivial_string<char_type> const &);
-template <typename Char>
-bool operator==(Char const * lhs, trivial_string<Char> const & rhs)
-{
-	return rhs.compare(trivial_string<Char>(lhs)) == 0;
-}
-
-
-template ostream & operator<<(ostream &, trivial_string<char> const &);
-template odocstream & operator<<(odocstream &, trivial_string<char_type> const &);
-template <typename Char>
-basic_ostream<Char, char_traits<Char> > &
-operator<<(basic_ostream<Char, char_traits<Char> > & os, trivial_string<Char> const & s)
-{
-	return os << basic_string<Char, char_traits<Char>, allocator<Char> >(s);
-}
-
-} // namespace lyx
-#endif
diff --git a/src/support/trivstring.h b/src/support/trivstring.h
deleted file mode 100644
index 3b47f6dc85..0000000000
--- a/src/support/trivstring.h
+++ /dev/null
@@ -1,114 +0,0 @@
-// -*- C++ -*-
-/**
- * \file trivstring.h
- * This file is part of LyX, the document processor.
- * Licence details can be found in the file COPYING.
- *
- * \author Georg Baum
- *
- * Full author contact details are available in file CREDITS.
- */
-
-#ifndef LYX_TRIVSTRING_H
-#define LYX_TRIVSTRING_H
-
-#ifdef STD_STRING_USES_COW
-#include <cstdlib>
-
-namespace lyx {
-
-/**
- * Trivial string class with almost no features.
- * The public interface is a subset of the std::basic_string interface.
- * The only important feature is that any read-only access does not need
- * synchronization between multiple threads, i.e. it is thread-safe without
- * locking.
- * Therefore you can safely use a const trivial_string object in multiple
- * threads at the same time. This is not the case for std::basic_string in some
- * STL implementations (e. g. GNU libcstd++, see bug 9336 and
- * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=21334.
- * This class should not be used for anything else than providing thread-safety.
- * It should be removed as soon as LyX requires C++11, and all supported STL
- * implementations provide a C++11 conformant std::basic_string.
- *
- * If you change anything in this class please ensure that the unit test
- * tests/check_trivstring.cpp still tests 100% of the public interface.
- */
-template <typename Char> class trivial_string
-{
-public:
-	/// Corresponding std::basic_string
-	typedef std::basic_string<Char, std::char_traits<Char>, std::allocator<Char> > _stdstring;
-	/// Construct an empty string
-	trivial_string() : size_(0), data_(0) {}
-	/// Construct a string from a copy of \p that
-	trivial_string(trivial_string const & that);
-	/// Construct a string from a copy of \p that
-	trivial_string(Char const * that, size_t n);
-	/// Construct a string from a copy of \p that
-	trivial_string(_stdstring const & that);
-	///
-	~trivial_string() { if (!use_sso()) delete[] data_; }
-	/// Assign a copy of \p that
-	trivial_string & operator=(trivial_string const & that);
-	/// Assign a copy of \p that
-	trivial_string & operator=(_stdstring const & that);
-	/// Exchange contents with contents of \p that
-	void swap(trivial_string & that);
-	/// The length of the string, excluding the final 0 character
-	size_t length() const { return size_; }
-	/// Is this string empty?
-	bool empty() const { return size_ == 0; }
-	/// Is this string ordered before, at the same position or after \p other?
-	int compare(trivial_string const & other) const;
-	/// Return substring of length \p n starting at \p pos
-	trivial_string substr(size_t pos = 0, size_t n = _stdstring::npos) const;
-	/// Create a copy as std::basic_string
-	operator _stdstring() const;
-	/// Return a C-compatible string, terminated by a 0 character.
-	/// This is never a copy and only valid for the life time of the trivial_string instance.
-	Char const * c_str() const;
-	/// Return character at position \p i (validity of \i is not checked)
-	Char operator[](size_t i) const;
-private:
-	/**
-	 * Whether short string optimization is used.
-	 * Short string optimization is a technique where no additional memory
-	 * needs to be allocated to store the string contents.
-	 * Instead, the memory which would be used to store the pointer to the
-	 * character buffer is reinterpreted to be a Char * buffer.
-	 * On most 64 bit systems and with Char == char this allows to store
-	 * strings of up to 7 characters without allocating additional memory.
-	 */
-	bool use_sso() const { return (size_ + 1) * sizeof(Char) <= sizeof(Char *); }
-	/// The character storage if sso is used
-	Char       * data_sso()       { return reinterpret_cast<Char *      >(&data_); }
-	/// The character storage if sso is used
-	Char const * data_sso() const { return reinterpret_cast<Char const *>(&data_); }
-	/// The length of the string, excluding the final 0 character
-	size_t size_;
-	/// The character storage
-	Char * data_;
-};
-
-
-/// Comparison operator (needed for std::set etc)
-template <typename Char> bool operator<(trivial_string<Char> const & lhs, trivial_string<Char> const & rhs);
-
-
-/// Equality operator
-template <typename Char> bool operator==(trivial_string<Char> const & lhs, trivial_string<Char> const & rhs);
-template <typename Char> bool operator==(trivial_string<Char> const & lhs, Char const * rhs);
-template <typename Char> bool operator==(Char const * lhs, trivial_string<Char> const & rhs);
-
-
-/// Stream output operator
-template <typename Char>
-std::basic_ostream<Char, std::char_traits<Char> > &
-operator<<(std::basic_ostream<Char, std::char_traits<Char> > &, trivial_string<Char> const &);
-
-} // namespace lyx
-#else
-#include <string>
-#endif
-#endif