diff --git a/guile/mu-guile-message.cc b/guile/mu-guile-message.cc
index 640d643b..3918b2b0 100644
--- a/guile/mu-guile-message.cc
+++ b/guile/mu-guile-message.cc
@@ -213,7 +213,7 @@ SCM_DEFINE(get_field,
 #undef FUNC_NAME
 
 static SCM
-contacts_to_list(MuMsg *msg, std::optional<Field::Id> field_id)
+contacts_to_list(MuMsg *msg, Option<Field::Id> field_id)
 {
 	SCM list{SCM_EOL};
 
@@ -252,7 +252,7 @@ SCM_DEFINE(get_contacts,
 	if (CONTACT_TYPE == SCM_BOOL_F)
 		return SCM_UNSPECIFIED; /* nothing to do */
 
-	std::optional<Field::Id> field_id;
+	Option<Field::Id> field_id;
 	if (CONTACT_TYPE == SCM_BOOL_T)
 		field_id = {}; /* get all */
 	else {
diff --git a/lib/message/mu-flags.hh b/lib/message/mu-flags.hh
index f424b5a1..651ede73 100644
--- a/lib/message/mu-flags.hh
+++ b/lib/message/mu-flags.hh
@@ -24,7 +24,8 @@
 #include <optional>
 #include <string_view>
 #include <array>
-#include "utils/mu-utils.hh"
+#include <utils/mu-utils.hh>
+#include <utils/mu-option.hh>
 
 namespace Mu {
 
@@ -146,16 +147,16 @@ constexpr void flag_infos_for_each(Func&& func)
  *
  * @param flag a singular flag
  *
- * @return the MessageFlagInfo, or std::nullopt in case of error.
+ * @return the MessageFlagInfo, or Nothing in case of error.
  */
-constexpr const std::optional<MessageFlagInfo>
+constexpr const Option<MessageFlagInfo>
 flag_info(Flags flag)
 {
 	constexpr auto upper = static_cast<unsigned>(Flags::_final_);
 	const auto     val   = static_cast<unsigned>(flag);
 
 	if (__builtin_popcount(val) != 1 || val >= upper)
-		return std::nullopt;
+		return Nothing;
 
 	return AllMessageFlagInfos[static_cast<unsigned>(__builtin_ctz(val))];
 }
@@ -167,14 +168,14 @@ flag_info(Flags flag)
  *
  * @return the MessageFlagInfo
  */
-constexpr const std::optional<MessageFlagInfo>
+constexpr const Option<MessageFlagInfo>
 flag_info(char shortcut)
 {
 	for (auto&& info : AllMessageFlagInfos)
 		if (info.shortcut == shortcut)
 			return info;
 
-	return std::nullopt;
+	return Nothing;
 }
 
 /**
@@ -184,14 +185,14 @@ flag_info(char shortcut)
  *
  * @return the MessageFlagInfo
  */
-constexpr const std::optional<MessageFlagInfo>
+constexpr const Option<MessageFlagInfo>
 flag_info(std::string_view name)
 {
 	for (auto&& info : AllMessageFlagInfos)
 		if (info.name == name)
 			return info;
 
-	return std::nullopt;
+	return Nothing;
 }
 
 /**
@@ -209,7 +210,7 @@ flag_info(std::string_view name)
  *
  * @return the (OR'ed) flags or Flags::None
  */
-constexpr std::optional<Flags>
+constexpr Option<Flags>
 flags_from_absolute_expr(std::string_view expr, bool ignore_invalid = false)
 {
 	Flags flags{Flags::None};
@@ -217,7 +218,7 @@ flags_from_absolute_expr(std::string_view expr, bool ignore_invalid = false)
 	for (auto&& kar : expr) {
 		if (const auto& info{flag_info(kar)}; !info) {
 			if (!ignore_invalid)
-				return std::nullopt;
+				return Nothing;
 		} else
 			flags |= info->flag;
 	}
@@ -242,24 +243,24 @@ flags_from_absolute_expr(std::string_view expr, bool ignore_invalid = false)
  *
  * @return new flags, or nullopt in case of error
  */
-constexpr std::optional<Flags>
+constexpr Option<Flags>
 flags_from_delta_expr(std::string_view expr, Flags flags,
-			      bool ignore_invalid = false)
+		      bool ignore_invalid = false)
 {
 	if (expr.size() % 2 != 0)
-		return std::nullopt;
+		return Nothing;
 
 	for (auto u = 0U; u != expr.size(); u += 2) {
 		if (const auto& info{flag_info(expr[u + 1])}; !info) {
 			if (!ignore_invalid)
-				return std::nullopt;
+				return Nothing;
 		} else {
 			switch (expr[u]) {
 			case '+': flags |= info->flag; break;
 			case '-': flags &= ~info->flag; break;
 			default:
 				if (!ignore_invalid)
-					return std::nullopt;
+					return Nothing;
 				break;
 			}
 		}
@@ -274,14 +275,14 @@ flags_from_delta_expr(std::string_view expr, Flags flags,
  * @param expr a flag expression, either 'delta' or 'absolute'
  * @param flags optional: existing flags or none. Required for delta.
  *
- * @return either messages flags or std::nullopt in case of error.
+ * @return either messages flags or Nothing in case of error.
  */
-constexpr std::optional<Flags>
+constexpr Option<Flags>
 flags_from_expr(std::string_view            expr,
-			std::optional<Flags> flags = std::nullopt)
+		Option<Flags> flags = Nothing)
 {
 	if (expr.empty())
-		return std::nullopt;
+		return Nothing;
 
 	if (expr[0] == '+' || expr[0] == '-')
 		return flags_from_delta_expr(
diff --git a/lib/mu-msg.cc b/lib/mu-msg.cc
index 41f80746..1ce4d896 100644
--- a/lib/mu-msg.cc
+++ b/lib/mu-msg.cc
@@ -636,7 +636,7 @@ get_all_contacts(MuMsg *self)
 }
 
 Mu::Contacts
-Mu::mu_msg_get_contacts(MuMsg *self, std::optional<Field::Id> field_id)
+Mu::mu_msg_get_contacts(MuMsg *self, Option<Field::Id> field_id)
 {
 	typedef const char*(*AddressFunc)(MuMsg*);
 	using	AddressInfo = std::pair<GMimeAddressType, AddressFunc>;
diff --git a/lib/mu-msg.hh b/lib/mu-msg.hh
index 7acd9917..f0962106 100644
--- a/lib/mu-msg.hh
+++ b/lib/mu-msg.hh
@@ -446,7 +446,7 @@ bool mu_msg_move_to_maildir(MuMsg*		msg,
  * @return a sequence
  */
 Mu::Contacts mu_msg_get_contacts (MuMsg *self,
-				  std::optional<Field::Id> field_id={});
+				  Option<Field::Id> field_id={});
 /**
  * create a 'display contact' from an email header To/Cc/Bcc/From-type address
  * ie., turn
diff --git a/lib/mu-query.cc b/lib/mu-query.cc
index d968d820..a6218c01 100644
--- a/lib/mu-query.cc
+++ b/lib/mu-query.cc
@@ -42,23 +42,23 @@ struct Query::Private {
 	// bool calculate_threads (Xapian::Enquire& enq, size maxnum);
 
 	Xapian::Enquire make_enquire(const std::string&       expr,
-				     std::optional<Field::Id> sortfield_id,
+				     Option<Field::Id> sortfield_id,
 				     QueryFlags               qflags) const;
 	Xapian::Enquire make_related_enquire(const StringSet&         thread_ids,
-					     std::optional<Field::Id> sortfield_id,
+					     Option<Field::Id> sortfield_id,
 					     QueryFlags               qflags) const;
 
 	Option<QueryResults> run_threaded(QueryResults&& qres, Xapian::Enquire& enq,
 					  QueryFlags qflags, size_t max_size) const;
 	Option<QueryResults> run_singular(const std::string&       expr,
-					  std::optional<Field::Id> sortfield_id,
+					  Option<Field::Id> sortfield_id,
 					  QueryFlags qflags, size_t maxnum) const;
 	Option<QueryResults> run_related(const std::string&       expr,
-					 std::optional<Field::Id> sortfield_id,
+					 Option<Field::Id> sortfield_id,
 					 QueryFlags qflags, size_t maxnum) const;
 
 	Option<QueryResults> run(const std::string&       expr,
-				 std::optional<Field::Id> sortfield_id, QueryFlags qflags,
+				 Option<Field::Id> sortfield_id, QueryFlags qflags,
 				 size_t maxnum) const;
 
 	size_t store_size() const { return store_.database().get_doccount(); }
@@ -84,7 +84,7 @@ sort_enquire(Xapian::Enquire& enq, Field::Id sortfield_id, QueryFlags qflags)
 
 Xapian::Enquire
 Query::Private::make_enquire(const std::string&       expr,
-			     std::optional<Field::Id> sortfield_id,
+			     Option<Field::Id> sortfield_id,
 			     QueryFlags               qflags) const
 {
 	Xapian::Enquire enq{store_.database()};
@@ -108,7 +108,7 @@ Query::Private::make_enquire(const std::string&       expr,
 
 Xapian::Enquire
 Query::Private::make_related_enquire(const StringSet& thread_ids,
-				     std::optional<Field::Id> sortfield_id,
+				     Option<Field::Id> sortfield_id,
 				     QueryFlags qflags) const
 {
 	Xapian::Enquire            enq{store_.database()};
@@ -156,7 +156,7 @@ Query::Private::run_threaded(QueryResults&& qres, Xapian::Enquire& enq, QueryFla
 
 Option<QueryResults>
 Query::Private::run_singular(const std::string& expr,
-			     std::optional<Field::Id> sortfield_id,
+			     Option<Field::Id> sortfield_id,
 			     QueryFlags qflags, size_t maxnum) const
 {
 	// i.e. a query _without_ related messages, but still possibly
@@ -197,7 +197,7 @@ opt_string(const Xapian::Document& doc, Field::Id id) noexcept
 
 Option<QueryResults>
 Query::Private::run_related(const std::string& expr,
-			    std::optional<Field::Id> sortfield_id,
+			    Option<Field::Id> sortfield_id,
 			    QueryFlags qflags, size_t maxnum) const
 {
 	// i.e. a query _with_ related messages and possibly with threading.
@@ -231,7 +231,7 @@ Query::Private::run_related(const std::string& expr,
 	// is unlimited and the sorting happens during threading.
 	auto r_enq = std::invoke([&]{
 		if (threading)
-			return make_related_enquire(minfo.thread_ids, std::nullopt, qflags);
+			return make_related_enquire(minfo.thread_ids, Nothing, qflags);
 		else
 			return make_related_enquire(minfo.thread_ids, sortfield_id, qflags);
 	});
@@ -244,7 +244,7 @@ Query::Private::run_related(const std::string& expr,
 
 Option<QueryResults>
 Query::Private::run(const std::string&                expr,
-		    std::optional<Field::Id> sortfield_id, QueryFlags qflags,
+		    Option<Field::Id> sortfield_id, QueryFlags qflags,
 		    size_t maxnum) const
 {
 	const auto eff_maxnum{maxnum == 0 ? store_size() : maxnum};
@@ -259,7 +259,7 @@ Query::Private::run(const std::string&                expr,
 }
 
 Option<QueryResults>
-Query::run(const std::string& expr, std::optional<Field::Id> sortfield_id,
+Query::run(const std::string& expr, Option<Field::Id> sortfield_id,
 	   QueryFlags qflags, size_t maxnum) const
 try {
 	// some flags are for internal use only.
diff --git a/lib/mu-query.hh b/lib/mu-query.hh
index 9101c876..92653969 100644
--- a/lib/mu-query.hh
+++ b/lib/mu-query.hh
@@ -21,12 +21,12 @@
 #define __MU_QUERY_HH__
 
 #include <memory>
-#include <optional>
 
 #include <glib.h>
 #include <mu-store.hh>
 #include <mu-query-results.hh>
 #include <utils/mu-utils.hh>
+#include <utils/mu-option.hh>
 #include <message/mu-message.hh>
 
 namespace Mu {
@@ -44,10 +44,10 @@ public:
 	 * @return the query-results, or Nothing in case of error.
 	 */
 
-	Option<QueryResults> run(const std::string&		expr	     = "",
-				 std::optional<Field::Id>	sortfield_id = {},
-				 QueryFlags			flags	     = QueryFlags::None,
-				 size_t				maxnum	     = 0) const;
+	Option<QueryResults> run(const std::string&	expr	     = "",
+				 Option<Field::Id>	sortfield_id = {},
+				 QueryFlags		flags	     = QueryFlags::None,
+				 size_t			maxnum	     = 0) const;
 
 	/**
 	 * run a Xapian query to count the number of matches; for the syntax, please
diff --git a/lib/mu-server.cc b/lib/mu-server.cc
index a4bdc00b..1303bc63 100644
--- a/lib/mu-server.cc
+++ b/lib/mu-server.cc
@@ -44,6 +44,7 @@
 
 #include "utils/mu-str.h"
 #include "utils/mu-utils.hh"
+#include "utils/mu-option.hh"
 #include "utils/mu-command-parser.hh"
 #include "utils/mu-readline.hh"
 
@@ -119,7 +120,7 @@ private:
 				const Option<QueryMatch&> qm,
 				MuMsgOptions              opts) const;
 
-	Sexp::List move_docid(Store::Id docid, std::optional<std::string> flagstr,
+	Sexp::List move_docid(Store::Id docid, Option<std::string> flagstr,
 			      bool new_name, bool no_view);
 
 	Sexp::List perform_move(Store::Id		docid,
@@ -814,7 +815,7 @@ Sexp::List
 Server::Private::perform_move(Store::Id                 docid,
 			      MuMsg*                    msg,
 			      const std::string&	maildirarg,
-			      Flags		flags,
+			      Flags			flags,
 			      bool                      new_name,
 			      bool                      no_view)
 {
@@ -852,9 +853,9 @@ Server::Private::perform_move(Store::Id                 docid,
 
 
 static Flags
-calculate_message_flags(MuMsg* msg, std::optional<std::string> flagopt)
+calculate_message_flags(MuMsg* msg, Option<std::string> flagopt)
 {
-	const auto flags = std::invoke([&]()->std::optional<Flags>{
+	const auto flags = std::invoke([&]()->Option<Flags>{
 			auto msgflags{mu_msg_get_flags(msg)};
 			if (!flagopt)
 				return mu_msg_get_flags(msg);
@@ -870,10 +871,10 @@ calculate_message_flags(MuMsg* msg, std::optional<std::string> flagopt)
 }
 
 Sexp::List
-Server::Private::move_docid(Store::Id			docid,
-			    std::optional<std::string>	flagopt,
-			    bool			new_name,
-			    bool			no_view)
+Server::Private::move_docid(Store::Id		docid,
+			    Option<std::string>	flagopt,
+			    bool		new_name,
+			    bool		no_view)
 {
 	if (docid == Store::InvalidId)
 		throw Error{Error::Code::InvalidArgument, "invalid docid"};
diff --git a/lib/mu-store.cc b/lib/mu-store.cc
index 01c62e93..043892a2 100644
--- a/lib/mu-store.cc
+++ b/lib/mu-store.cc
@@ -631,7 +631,7 @@ Store::lock() const
 
 Option<QueryResults>
 Store::run_query(const std::string& expr,
-		 std::optional<Field::Id> sortfield_id,
+		 Option<Field::Id> sortfield_id,
 		 QueryFlags flags, size_t maxnum) const
 {
 	return xapian_try([&] {
diff --git a/lib/mu-store.hh b/lib/mu-store.hh
index 77241325..5fd2507f 100644
--- a/lib/mu-store.hh
+++ b/lib/mu-store.hh
@@ -34,6 +34,8 @@
 #include <index/mu-indexer.hh>
 #include <mu-query-results.hh>
 #include <utils/mu-utils.hh>
+#include <utils/mu-option.hh>
+
 #include <message/mu-message.hh>
 
 namespace Mu {
@@ -155,10 +157,10 @@ public:
 	 * @return the query-results, or Nothing in case of error.
 	 */
 	std::mutex& lock() const;
-	Option<QueryResults> run_query(const std::string&	expr        = "",
-				       std::optional<Field::Id>    sortfield_id = {},
-				       QueryFlags		flags       = QueryFlags::None,
-				       size_t			maxnum      = 0) const;
+	Option<QueryResults> run_query(const std::string&	expr	     = "",
+				       Option<Field::Id>	sortfield_id = {},
+				       QueryFlags		flags	     = QueryFlags::None,
+				       size_t			maxnum	     = 0) const;
 
 	/**
 	 * run a Xapian query merely to count the number of matches; for the
diff --git a/lib/utils/mu-command-parser.cc b/lib/utils/mu-command-parser.cc
index 05f1e02d..40be1e9c 100644
--- a/lib/utils/mu-command-parser.cc
+++ b/lib/utils/mu-command-parser.cc
@@ -32,16 +32,16 @@ Command::invoke(const Command::CommandMap& cmap, const Sexp& call)
 {
 	if (!call.is_call()) {
 		throw Mu::Error{Error::Code::Command,
-		                "expected call-sexpr but got %s",
-		                call.to_sexp_string().c_str()};
+				"expected call-sexpr but got %s",
+				call.to_sexp_string().c_str()};
 	}
 
 	const auto& params{call.list()};
 	const auto  cmd_it = cmap.find(params.at(0).value());
 	if (cmd_it == cmap.end())
 		throw Mu::Error{Error::Code::Command,
-		                "unknown command in call %s",
-		                call.to_sexp_string().c_str()};
+				"unknown command in call %s",
+				call.to_sexp_string().c_str()};
 
 	const auto& cinfo{cmd_it->second};
 
@@ -65,9 +65,9 @@ Command::invoke(const Command::CommandMap& cmap, const Sexp& call)
 		if (param_it == params.end()) {
 			if (arginfo.required)
 				throw Mu::Error{Error::Code::Command,
-				                "missing required parameter %s in call %s",
-				                argname.c_str(),
-				                call.to_sexp_string().c_str()};
+						"missing required parameter %s in call %s",
+						argname.c_str(),
+						call.to_sexp_string().c_str()};
 			continue; // not required
 		}
 
@@ -75,11 +75,11 @@ Command::invoke(const Command::CommandMap& cmap, const Sexp& call)
 		// "no value"
 		if (param_it->type() != arginfo.type && !(param_it->is_nil()))
 			throw Mu::Error{Error::Code::Command,
-			                "parameter %s expects type %s, but got %s in call %s",
-			                argname.c_str(),
-			                to_string(arginfo.type).c_str(),
-			                to_string(param_it->type()).c_str(),
-			                call.to_sexp_string().c_str()};
+					"parameter %s expects type %s, but got %s in call %s",
+					argname.c_str(),
+					to_string(arginfo.type).c_str(),
+					to_string(param_it->type()).c_str(),
+					call.to_sexp_string().c_str()};
 	}
 
 	// all passed parameters must be known
@@ -88,9 +88,9 @@ Command::invoke(const Command::CommandMap& cmap, const Sexp& call)
 			    return params.at(i).value() == arg.first;
 		    }))
 			throw Mu::Error{Error::Code::Command,
-			                "unknown parameter %s in call %s",
-			                params.at(i).value().c_str(),
-			                call.to_sexp_string().c_str()};
+					"unknown parameter %s in call %s",
+					params.at(i).value().c_str(),
+					call.to_sexp_string().c_str()};
 	}
 
 	if (cinfo.handler)
@@ -105,8 +105,8 @@ find_param_node(const Parameters& params, const std::string& argname)
 
 	if (argname.empty() || argname.at(0) != ':')
 		throw Error(Error::Code::InvalidArgument,
-		            "property key must start with ':' but got '%s')",
-		            argname.c_str());
+			    "property key must start with ':' but got '%s')",
+			    argname.c_str());
 
 	for (size_t i = 1; i < params.size(); i += 2) {
 		if (i + 1 != params.size() && params.at(i).is_symbol() &&
@@ -121,63 +121,63 @@ static Error
 wrong_type(Sexp::Type expected, Sexp::Type got)
 {
 	return Error(Error::Code::InvalidArgument,
-	             "expected <%s> but got <%s>",
-	             to_string(expected).c_str(),
-	             to_string(got).c_str());
+		     "expected <%s> but got <%s>",
+		     to_string(expected).c_str(),
+		     to_string(got).c_str());
 }
 
-std::optional<std::string>
+Option<std::string>
 Command::get_string(const Parameters& params, const std::string& argname)
 {
 	const auto it = find_param_node(params, argname);
 	if (it == params.end() || it->is_nil())
-		return std::nullopt;
+		return Nothing;
 	else if (!it->is_string())
 		throw wrong_type(Sexp::Type::String, it->type());
 	else
 		return it->value();
 }
 
-std::optional<std::string>
+Option<std::string>
 Command::get_symbol(const Parameters& params, const std::string& argname)
 {
 	const auto it = find_param_node(params, argname);
 	if (it == params.end() || it->is_nil())
-		return std::nullopt;
+		return Nothing;
 	else if (!it->is_symbol())
 		throw wrong_type(Sexp::Type::Symbol, it->type());
 	else
 		return it->value();
 }
 
-std::optional<int>
+Option<int>
 Command::get_int(const Parameters& params, const std::string& argname)
 {
 	const auto it = find_param_node(params, argname);
 	if (it == params.end() || it->is_nil())
-		return std::nullopt;
+		return Nothing;
 	else if (!it->is_number())
 		throw wrong_type(Sexp::Type::Number, it->type());
 	else
 		return ::atoi(it->value().c_str());
 }
 
-std::optional<unsigned>
+Option<unsigned>
 Command::get_unsigned(const Parameters& params, const std::string& argname)
 {
 	if (auto val = get_int(params, argname); val && *val >= 0)
 		return val;
 	else
-		return std::nullopt;
+		return Nothing;
 }
 
 
-std::optional<bool>
+Option<bool>
 Command::get_bool(const Parameters& params, const std::string& argname)
 {
 	const auto it = find_param_node(params, argname);
 	if (it == params.end())
-		return std::nullopt;
+		return Nothing;
 	else if (!it->is_symbol())
 		throw wrong_type(Sexp::Type::Symbol, it->type());
 	else
diff --git a/lib/utils/mu-command-parser.hh b/lib/utils/mu-command-parser.hh
index b7a47763..751e5d8e 100644
--- a/lib/utils/mu-command-parser.hh
+++ b/lib/utils/mu-command-parser.hh
@@ -26,10 +26,10 @@
 #include <unordered_map>
 #include <functional>
 #include <algorithm>
-#include <optional>
 
 #include "utils/mu-error.hh"
 #include "utils/mu-sexp.hh"
+#include "utils/mu-option.hh"
 
 namespace Mu {
 namespace Command {
@@ -62,11 +62,11 @@ using ArgMap = std::unordered_map<std::string, ArgInfo>;
 // The parameters to a Handler.
 using Parameters = Sexp::Seq;
 
-std::optional<int>          get_int(const Parameters& parms, const std::string& argname);
-std::optional<unsigned>     get_unsigned(const Parameters& parms, const std::string& argname);
-std::optional<bool>         get_bool(const Parameters& parms, const std::string& argname);
-std::optional<std::string>  get_string(const Parameters& parms, const std::string& argname);
-std::optional<std::string>  get_symbol(const Parameters& parms, const std::string& argname);
+Option<int>		get_int(const Parameters& parms, const std::string& argname);
+Option<unsigned>	get_unsigned(const Parameters& parms, const std::string& argname);
+Option<bool>		get_bool(const Parameters& parms, const std::string& argname);
+Option<std::string>	get_string(const Parameters& parms, const std::string& argname);
+Option<std::string>	get_symbol(const Parameters& parms, const std::string& argname);
 
 std::vector<std::string> get_string_vec(const Parameters& params, const std::string& argname);
 
@@ -86,7 +86,7 @@ static inline std::string
 get_string_or(const Parameters& parms, const std::string& arg, const std::string& alt = ""){
 	return get_string(parms, arg).value_or(alt);
 }
-		
+
 static inline std::string
 get_symbol_or(const Parameters& parms, const std::string& arg, const std::string& alt = "nil") {
 	return get_symbol(parms, arg).value_or(alt);