diff --git a/src/OpenFOAM/db/dictionary/dictionary.C b/src/OpenFOAM/db/dictionary/dictionary.C
index 699cdffeb8..851b9a9a46 100644
--- a/src/OpenFOAM/db/dictionary/dictionary.C
+++ b/src/OpenFOAM/db/dictionary/dictionary.C
@@ -368,9 +368,9 @@ const Foam::entry& Foam::dictionary::lookupEntry
     enum keyType::option matchOpt
 ) const
 {
-    const const_searcher finder(csearch(keyword, matchOpt));
+    const entry* eptr = findEntry(keyword, matchOpt);
 
-    if (!finder.good())
+    if (!eptr)
     {
         FatalIOErrorInFunction(*this)
             << "Entry '" << keyword << "' not found in dictionary "
@@ -378,7 +378,7 @@ const Foam::entry& Foam::dictionary::lookupEntry
             << exit(FatalIOError);
     }
 
-    return finder.ref();
+    return *eptr;
 }
 
 
@@ -504,12 +504,12 @@ Foam::dictionary& Foam::dictionary::subDictOrAdd
 {
     searcher finder(search(keyword, matchOpt));
 
-    dictionary* ptr = finder.dictPtr();
+    dictionary* dictPtr = finder.dictPtr();
 
-    if (ptr)
+    if (dictPtr)
     {
         // Found and a sub-dictionary
-        return *ptr;
+        return *dictPtr;
     }
 
     if (finder.good())
@@ -521,9 +521,9 @@ Foam::dictionary& Foam::dictionary::subDictOrAdd
             << exit(FatalIOError);
     }
 
-    ptr = this->set(keyword, dictionary())->dictPtr();
+    dictPtr = this->set(keyword, dictionary())->dictPtr();
 
-    if (!ptr)
+    if (!dictPtr)
     {
         FatalIOErrorInFunction(*this)
             << "Failed to insert sub-dictionary '" << keyword
@@ -532,7 +532,7 @@ Foam::dictionary& Foam::dictionary::subDictOrAdd
             << exit(FatalIOError);
     }
 
-    return *ptr;
+    return *dictPtr;
 }
 
 
@@ -545,10 +545,12 @@ Foam::dictionary Foam::dictionary::subOrEmptyDict
 {
     const const_searcher finder(csearch(keyword, matchOpt));
 
-    if (finder.isDict())
+    const dictionary* dictPtr = finder.dictPtr();
+
+    if (dictPtr)
     {
         // Found and a sub-dictionary
-        return finder.dict();
+        return *dictPtr;
     }
 
     if (mandatory)
@@ -581,10 +583,12 @@ const Foam::dictionary& Foam::dictionary::optionalSubDict
 {
     const const_searcher finder(csearch(keyword, matchOpt));
 
-    if (finder.isDict())
+    const dictionary* dictPtr = finder.dictPtr();
+
+    if (dictPtr)
     {
         // Found and a sub-dictionary
-        return finder.dict();
+        return *dictPtr;
     }
 
     if (finder.good())
@@ -787,10 +791,12 @@ Foam::entry* Foam::dictionary::set(entry* entryPtr)
     // Find non-recursive with patterns
     searcher finder(search(entryPtr->keyword(), keyType::REGEX));
 
+    dictionary* dictPtr = finder.dictPtr();
+
     // Clear dictionary so merge acts like overwrite
-    if (finder.isDict())
+    if (dictPtr)
     {
-        finder.dict().clear();
+        dictPtr->clear();
     }
 
     return add(entryPtr, true);
diff --git a/src/OpenFOAM/db/dictionary/dictionary.H b/src/OpenFOAM/db/dictionary/dictionary.H
index d8b75aae51..9b7b2ff50d 100644
--- a/src/OpenFOAM/db/dictionary/dictionary.H
+++ b/src/OpenFOAM/db/dictionary/dictionary.H
@@ -98,6 +98,7 @@ SeeAlso
 #include "wordList.H"
 #include "className.H"
 #include "refPtr.H"
+#include "IOobjectOption.H"
 
 // Some common data types
 #include "label.H"
@@ -175,14 +176,14 @@ public:
 
             //- Construct for the given dictionary context.
             //  Allow implicit conversion
-            Searcher(dict_pointer dict)
+            Searcher(dict_pointer dict) noexcept
             :
                 dict_(dict),
                 eptr_(nullptr)
             {}
 
             //- Assign the entry
-            void set(pointer eptr)
+            void set(pointer eptr) noexcept
             {
                 eptr_ = eptr;
             }
@@ -191,7 +192,7 @@ public:
         public:
 
             //- Default construct
-            Searcher()
+            constexpr Searcher() noexcept
             :
                 dict_(nullptr),
                 eptr_(nullptr)
@@ -199,34 +200,19 @@ public:
 
 
             //- True if entry was found
-            bool good() const noexcept
-            {
-                return eptr_;
-            }
+            bool good() const noexcept { return eptr_; }
 
             //- True if entry was found
-            bool found() const noexcept
-            {
-                return eptr_;
-            }
+            bool found() const noexcept { return eptr_; }
 
             //- The containing dictionary context
-            dict_reference context() const
-            {
-                return *dict_;
-            }
+            dict_reference context() const { return *dict_; }
 
             //- A pointer to the entry (nullptr if not found)
-            pointer ptr() const noexcept
-            {
-                return eptr_;
-            }
+            pointer ptr() const noexcept { return eptr_; }
 
             //- A reference to the entry (Error if not found)
-            reference ref() const
-            {
-                return *eptr_;
-            }
+            reference ref() const { return *eptr_; }
 
             //- True if found entry is a dictionary.
             bool isDict() const noexcept
@@ -507,26 +493,26 @@ public:
         tokenList tokens() const;
 
 
-    // Search and lookup
+    // Searching
 
-        //- Search for an entry (const access) with the given keyword.
+        //- Find an entry (const access) with the given keyword.
         //
         //  \param keyword the keyword to search for
         //  \param matchOpt search mode (default: non-recursive with patterns)
         //
-        //  \return True if entry was found
-        inline bool found
+        //  \return pointer to the entry found or a nullptr.
+        inline const entry* findEntry
         (
             const word& keyword,
             enum keyType::option matchOpt = keyType::REGEX
         ) const;
 
-        //- Find for an entry (non-const access) with the given keyword.
+        //- Find an entry (non-const access) with the given keyword.
         //
         //  \param keyword the keyword to search for
         //  \param matchOpt search mode (default: non-recursive with patterns)
         //
-        //  \return the entry pointer found or a nullptr.
+        //  \return pointer to the entry found or a nullptr.
         inline entry* findEntry
         (
             const word& keyword,
@@ -538,8 +524,8 @@ public:
         //  \param keyword the keyword to search for
         //  \param matchOpt search mode (default: non-recursive with patterns)
         //
-        //  \return the entry pointer found or a nullptr.
-        inline const entry* findEntry
+        //  \return True if entry was found
+        inline bool found
         (
             const word& keyword,
             enum keyType::option matchOpt = keyType::REGEX
@@ -553,7 +539,7 @@ public:
         //  \param keyword the keyword to search for
         //  \param matchOpt search mode (default: non-recursive with patterns)
         //
-        //  \return the entry pointer found or a nullptr.
+        //  \return pointer to the entry found or a nullptr.
         inline const entry* findScoped
         (
             const word& keyword,
@@ -561,7 +547,20 @@ public:
         ) const;
 
         //- Find and return a sub-dictionary pointer if present
-        //  (and a sub-dictionary) otherwise return nullptr.
+        //- (and a sub-dictionary) otherwise return nullptr.
+        //
+        //  \param keyword the keyword to search for
+        //  \param matchOpt search mode (default: non-recursive with patterns)
+        //
+        //  \return pointer to sub-dictionary found or a nullptr.
+        inline const dictionary* findDict
+        (
+            const word& keyword,
+            enum keyType::option matchOpt = keyType::REGEX
+        ) const;
+
+        //- Find and return a sub-dictionary pointer if present
+        //- (and a sub-dictionary) otherwise return nullptr.
         //
         //  \param keyword the keyword to search for
         //  \param matchOpt search mode (default: non-recursive with patterns)
@@ -573,19 +572,21 @@ public:
             enum keyType::option matchOpt = keyType::REGEX
         );
 
-        //- Find and return a sub-dictionary pointer if present
-        //  (and a sub-dictionary) otherwise return nullptr.
+        //- Find a sub-dictionary.
         //
         //  \param keyword the keyword to search for
         //  \param matchOpt search mode (default: non-recursive with patterns)
         //
-        //  \return pointer to sub-dictionary found or a nullptr.
-        inline const dictionary* findDict
+        //  \return true if the sub-dictionary was found
+        inline bool isDict
         (
             const word& keyword,
             enum keyType::option matchOpt = keyType::REGEX
         ) const;
 
+
+    // Lookup
+
         //- Search for an entry (const access) with the given keyword.
         //
         //  \param keyword the keyword to search for
@@ -659,16 +660,16 @@ public:
         //  \param keyword the keyword to search for
         //  \param val the value to read into
         //  \param matchOpt search mode (default: non-recursive with patterns)
-        //  \param mandatory the keyword is mandatory (default: true)
+        //  \param readOpt the entry is required/optional (default: MUST_READ)
         //
-        //  \return true if the entry was found.
+        //  \return true if the entry was read
         template<class T>
         bool readEntry
         (
             const word& keyword,
             T& val,
             enum keyType::option matchOpt = keyType::REGEX,
-            bool mandatory = true
+            IOobjectOption::readOption readOpt = IOobjectOption::MUST_READ
         ) const;
 
         //- Find an entry if present, and assign to T val.
@@ -678,7 +679,7 @@ public:
         //  \param val the value to read into
         //  \param matchOpt search mode (default: non-recursive with patterns)
         //
-        //  \return true if the entry was found.
+        //  \return true if the entry was read
         template<class T>
         bool readIfPresent
         (
@@ -742,9 +743,9 @@ public:
         //  \param val the value to read into
         //  \param pred the value check predicate
         //  \param matchOpt search mode (default: non-recursive with patterns)
-        //  \param mandatory the keyword is mandatory (default: true)
+        //  \param readOpt the entry is required/optional (default: MUST_READ)
         //
-        //  \return true if the entry was found.
+        //  \return true if the entry was read
         template<class T, class Predicate>
         bool readCheck
         (
@@ -752,7 +753,7 @@ public:
             T& val,
             const Predicate& pred,
             enum keyType::option matchOpt = keyType::REGEX,
-            bool mandatory = true
+            IOobjectOption::readOption readOpt = IOobjectOption::MUST_READ
         ) const;
 
         //- Find an entry if present, and assign to T val.
@@ -763,7 +764,7 @@ public:
         //  \param pred the value check predicate
         //  \param matchOpt search mode (default: non-recursive with patterns)
         //
-        //  \return true if the entry was found.
+        //  \return true if the entry read
         template<class T, class Predicate>
         bool readCheckIfPresent
         (
@@ -773,18 +774,6 @@ public:
             enum keyType::option matchOpt = keyType::REGEX
         ) const;
 
-        //- Check if entry is found and is a sub-dictionary.
-        //
-        //  \param keyword the keyword to search for
-        //  \param matchOpt search mode (default: non-recursive with patterns)
-        //
-        //  \return true if the entry was found.
-        inline bool isDict
-        (
-            const word& keyword,
-            enum keyType::option matchOpt = keyType::REGEX
-        ) const;
-
         //- Find and return a sub-dictionary.
         //  Fatal if the entry does not exist or is not a sub-dictionary.
         //
@@ -1120,19 +1109,6 @@ public:
             enum keyType::option matchOpt = keyType::REGEX
         ) const;
 
-        //- Search dictionary for given keyword and any compatibility names
-        //
-        //  \param keyword the keyword to search for
-        //  \param compat list of old compatibility keywords and the last
-        //      OpenFOAM version for which they were used.
-        //  \param matchOpt search mode (default: non-recursive with patterns)
-        bool foundCompat
-        (
-            const word& keyword,
-            std::initializer_list<std::pair<const char*,int>> compat,
-            enum keyType::option matchOpt = keyType::REGEX
-        ) const;
-
         //- Find and return an entry pointer if present, or return a nullptr,
         //- using any compatibility names if needed.
         //
@@ -1147,6 +1123,19 @@ public:
             enum keyType::option matchOpt
         ) const;
 
+        //- Search dictionary for given keyword and any compatibility names
+        //
+        //  \param keyword the keyword to search for
+        //  \param compat list of old compatibility keywords and the last
+        //      OpenFOAM version for which they were used.
+        //  \param matchOpt search mode (default: non-recursive with patterns)
+        bool foundCompat
+        (
+            const word& keyword,
+            std::initializer_list<std::pair<const char*,int>> compat,
+            enum keyType::option matchOpt = keyType::REGEX
+        ) const;
+
         //- Find and return an entry if present, otherwise FatalIOError,
         //- using any compatibility names if needed.
         //
@@ -1217,9 +1206,9 @@ public:
         //      OpenFOAM version for which they were used.
         //  \param val the value to read
         //  \param matchOpt search mode (default: non-recursive with patterns)
-        //  \param mandatory the keyword is mandatory (default: true)
+        //  \param readOpt the entry is required/optional (default: MUST_READ)
         //
-        //  \return true if the entry was found.
+        //  \return true if the entry was read
         template<class T>
         bool readCompat
         (
@@ -1227,7 +1216,7 @@ public:
             std::initializer_list<std::pair<const char*,int>> compat,
             T& val,
             enum keyType::option matchOpt = keyType::REGEX,
-            bool mandatory = true
+            IOobjectOption::readOption readOpt = IOobjectOption::MUST_READ
         ) const;
 
         //- Find an entry if present, and assign to T val
diff --git a/src/OpenFOAM/db/dictionary/dictionaryCompat.C b/src/OpenFOAM/db/dictionary/dictionaryCompat.C
index 67fc777866..13ccb8adf8 100644
--- a/src/OpenFOAM/db/dictionary/dictionaryCompat.C
+++ b/src/OpenFOAM/db/dictionary/dictionaryCompat.C
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2017-2021 OpenCFD Ltd.
+    Copyright (C) 2017-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -71,17 +71,6 @@ Foam::dictionary::const_searcher Foam::dictionary::csearchCompat
 }
 
 
-bool Foam::dictionary::foundCompat
-(
-    const word& keyword,
-    std::initializer_list<std::pair<const char*,int>> compat,
-    enum keyType::option matchOpt
-) const
-{
-    return csearchCompat(keyword, compat, matchOpt).good();
-}
-
-
 const Foam::entry* Foam::dictionary::findCompat
 (
     const word& keyword,
@@ -93,6 +82,17 @@ const Foam::entry* Foam::dictionary::findCompat
 }
 
 
+bool Foam::dictionary::foundCompat
+(
+    const word& keyword,
+    std::initializer_list<std::pair<const char*,int>> compat,
+    enum keyType::option matchOpt
+) const
+{
+    return static_cast<bool>(findCompat(keyword, compat, matchOpt));
+}
+
+
 const Foam::entry& Foam::dictionary::lookupEntryCompat
 (
     const word& keyword,
@@ -100,9 +100,9 @@ const Foam::entry& Foam::dictionary::lookupEntryCompat
     enum keyType::option matchOpt
 ) const
 {
-    const const_searcher finder(csearchCompat(keyword, compat, matchOpt));
+    const entry* eptr = findCompat(keyword, compat, matchOpt);
 
-    if (!finder.good())
+    if (!eptr)
     {
         FatalIOErrorInFunction(*this)
             << "Entry '" << keyword << "' not found in dictionary "
@@ -110,7 +110,7 @@ const Foam::entry& Foam::dictionary::lookupEntryCompat
             << exit(FatalIOError);
     }
 
-    return finder.ref();
+    return *eptr;
 }
 
 
diff --git a/src/OpenFOAM/db/dictionary/dictionaryI.H b/src/OpenFOAM/db/dictionary/dictionaryI.H
index af4e791c96..ad7f29df04 100644
--- a/src/OpenFOAM/db/dictionary/dictionaryI.H
+++ b/src/OpenFOAM/db/dictionary/dictionaryI.H
@@ -83,13 +83,13 @@ inline const Foam::dictionary& Foam::dictionary::parent() const noexcept
 }
 
 
-inline bool Foam::dictionary::found
+inline const Foam::entry* Foam::dictionary::findEntry
 (
     const word& keyword,
     enum keyType::option matchOpt
 ) const
 {
-    return csearch(keyword, matchOpt).good();
+    return csearch(keyword, matchOpt).ptr();
 }
 
 
@@ -99,17 +99,17 @@ inline Foam::entry* Foam::dictionary::findEntry
     enum keyType::option matchOpt
 )
 {
-    return search(keyword, matchOpt).ptr();
+    return const_cast<entry*>(csearch(keyword, matchOpt).ptr());
 }
 
 
-inline const Foam::entry* Foam::dictionary::findEntry
+inline bool Foam::dictionary::found
 (
     const word& keyword,
     enum keyType::option matchOpt
 ) const
 {
-    return csearch(keyword, matchOpt).ptr();
+    return static_cast<bool>(findEntry(keyword, matchOpt));
 }
 
 
@@ -123,16 +123,6 @@ inline const Foam::entry* Foam::dictionary::findScoped
 }
 
 
-inline Foam::dictionary* Foam::dictionary::findDict
-(
-    const word& keyword,
-    enum keyType::option matchOpt
-)
-{
-    return search(keyword, matchOpt).dictPtr();
-}
-
-
 inline const Foam::dictionary* Foam::dictionary::findDict
 (
     const word& keyword,
@@ -143,13 +133,23 @@ inline const Foam::dictionary* Foam::dictionary::findDict
 }
 
 
+inline Foam::dictionary* Foam::dictionary::findDict
+(
+    const word& keyword,
+    enum keyType::option matchOpt
+)
+{
+    return const_cast<dictionary*>(csearch(keyword, matchOpt).dictPtr());
+}
+
+
 inline bool Foam::dictionary::isDict
 (
     const word& keyword,
     enum keyType::option matchOpt
 ) const
 {
-    return csearch(keyword, matchOpt).isDict();
+    return static_cast<bool>(findDict(keyword, matchOpt));
 }
 
 
diff --git a/src/OpenFOAM/db/dictionary/dictionaryTemplates.C b/src/OpenFOAM/db/dictionary/dictionaryTemplates.C
index 454100e2aa..7d97c858a0 100644
--- a/src/OpenFOAM/db/dictionary/dictionaryTemplates.C
+++ b/src/OpenFOAM/db/dictionary/dictionaryTemplates.C
@@ -151,13 +151,13 @@ T Foam::dictionary::getOrDefault
     enum keyType::option matchOpt
 ) const
 {
-    const const_searcher finder(csearch(keyword, matchOpt));
+    const entry* eptr = csearch(keyword, matchOpt).ptr();
 
-    if (finder.good())
+    if (eptr)
     {
         T val;
 
-        ITstream& is = finder.ptr()->stream();
+        ITstream& is = eptr->stream();
         is >> val;
 
         checkITstream(is, keyword);
@@ -181,13 +181,13 @@ T Foam::dictionary::getOrAdd
     enum keyType::option matchOpt
 )
 {
-    const const_searcher finder(csearch(keyword, matchOpt));
+    const entry* eptr = csearch(keyword, matchOpt).ptr();
 
-    if (finder.good())
+    if (eptr)
     {
         T val;
 
-        ITstream& is = finder.ptr()->stream();
+        ITstream& is = eptr->stream();
         is >> val;
 
         checkITstream(is, keyword);
@@ -223,13 +223,13 @@ T Foam::dictionary::getCheckOrDefault
     }
     #endif
 
-    const const_searcher finder(csearch(keyword, matchOpt));
+    const entry* eptr = csearch(keyword, matchOpt).ptr();
 
-    if (finder.good())
+    if (eptr)
     {
         T val;
 
-        ITstream& is = finder.ptr()->stream();
+        ITstream& is = eptr->stream();
         is >> val;
 
         checkITstream(is, keyword);
@@ -269,13 +269,13 @@ T Foam::dictionary::getCheckOrAdd
     }
     #endif
 
-    const const_searcher finder(csearch(keyword, matchOpt));
+    const entry* eptr = csearch(keyword, matchOpt).ptr();
 
-    if (finder.good())
+    if (eptr)
     {
         T val;
 
-        ITstream& is = finder.ptr()->stream();
+        ITstream& is = eptr->stream();
         is >> val;
 
         checkITstream(is, keyword);
@@ -303,21 +303,26 @@ bool Foam::dictionary::readEntry
     const word& keyword,
     T& val,
     enum keyType::option matchOpt,
-    bool mandatory
+    IOobjectOption::readOption readOpt
 ) const
 {
-    const const_searcher finder(csearch(keyword, matchOpt));
-
-    if (finder.good())
+    if (readOpt == IOobjectOption::NO_READ)
     {
-        ITstream& is = finder.ptr()->stream();
+        return false;
+    }
+
+    const entry* eptr = csearch(keyword, matchOpt).ptr();
+
+    if (eptr)
+    {
+        ITstream& is = eptr->stream();
         is >> val;
 
         checkITstream(is, keyword);
 
         return true;
     }
-    else if (mandatory)
+    else if (IOobjectOption::isReadRequired(readOpt))
     {
         FatalIOErrorInFunction(*this)
             << "Entry '" << keyword << "' not found in dictionary "
@@ -336,14 +341,19 @@ bool Foam::dictionary::readCheck
     T& val,
     const Predicate& pred,
     enum keyType::option matchOpt,
-    bool mandatory
+    IOobjectOption::readOption readOpt
 ) const
 {
-    const const_searcher finder(csearch(keyword, matchOpt));
-
-    if (finder.good())
+    if (readOpt == IOobjectOption::NO_READ)
     {
-        ITstream& is = finder.ptr()->stream();
+        return false;
+    }
+
+    const entry* eptr = csearch(keyword, matchOpt).ptr();
+
+    if (eptr)
+    {
+        ITstream& is = eptr->stream();
         is >> val;
 
         checkITstream(is, keyword);
@@ -355,7 +365,7 @@ bool Foam::dictionary::readCheck
 
         return true;
     }
-    else if (mandatory)
+    else if (IOobjectOption::isReadRequired(readOpt))
     {
         FatalIOErrorInFunction(*this)
             << "Entry '" << keyword << "' not found in dictionary "
@@ -374,21 +384,26 @@ bool Foam::dictionary::readCompat
     std::initializer_list<std::pair<const char*,int>> compat,
     T& val,
     enum keyType::option matchOpt,
-    bool mandatory
+    IOobjectOption::readOption readOpt
 ) const
 {
-    const const_searcher finder(csearchCompat(keyword, compat, matchOpt));
-
-    if (finder.good())
+    if (readOpt == IOobjectOption::NO_READ)
     {
-        ITstream& is = finder.ptr()->stream();
+        return false;
+    }
+
+    const entry* eptr = csearchCompat(keyword, compat, matchOpt).ptr();
+
+    if (eptr)
+    {
+        ITstream& is = eptr->stream();
         is >> val;
 
         checkITstream(is, keyword);
 
         return true;
     }
-    else if (mandatory)
+    else if (IOobjectOption::isReadRequired(readOpt))
     {
         FatalIOErrorInFunction(*this)
             << "Entry '" << keyword << "' not found in dictionary "
@@ -408,8 +423,14 @@ bool Foam::dictionary::readIfPresent
     enum keyType::option matchOpt
 ) const
 {
-    // Read is non-mandatory
-    return readEntry<T>(keyword, val, matchOpt, false);
+    // Reading is optional
+    return readEntry<T>
+    (
+        keyword,
+        val,
+        matchOpt,
+        IOobjectOption::READ_IF_PRESENT
+    );
 }
 
 
@@ -422,8 +443,15 @@ bool Foam::dictionary::readCheckIfPresent
     enum keyType::option matchOpt
 ) const
 {
-    // Read is non-mandatory
-    return readCheck<T, Predicate>(keyword, val, pred, matchOpt, false);
+    // Reading is optional
+    return readCheck<T, Predicate>
+    (
+        keyword,
+        val,
+        pred,
+        matchOpt,
+        IOobjectOption::READ_IF_PRESENT
+    );
 }
 
 
@@ -436,13 +464,13 @@ T Foam::dictionary::getOrDefaultCompat
     enum keyType::option matchOpt
 ) const
 {
-    const const_searcher finder(csearchCompat(keyword, compat, matchOpt));
+    const entry* eptr = csearchCompat(keyword, compat, matchOpt).ptr();
 
-    if (finder.good())
+    if (eptr)
     {
         T val;
 
-        ITstream& is = finder.ptr()->stream();
+        ITstream& is = eptr->stream();
         is >> val;
 
         checkITstream(is, keyword);
@@ -467,8 +495,15 @@ bool Foam::dictionary::readIfPresentCompat
     enum keyType::option matchOpt
 ) const
 {
-    // Read is non-mandatory
-    return readCompat<T>(keyword, compat, val, matchOpt, false);
+    // Reading is optional
+    return readCompat<T>
+    (
+        keyword,
+        compat,
+        val,
+        matchOpt,
+        IOobjectOption::READ_IF_PRESENT
+    );
 }
 
 
diff --git a/src/OpenFOAM/expressions/exprString/exprString.C b/src/OpenFOAM/expressions/exprString/exprString.C
index 7a156b30bd..7ffb0f4b36 100644
--- a/src/OpenFOAM/expressions/exprString/exprString.C
+++ b/src/OpenFOAM/expressions/exprString/exprString.C
@@ -74,10 +74,10 @@ bool Foam::expressions::exprString::readEntry
 (
     const word& keyword,
     const dictionary& dict,
-    bool mandatory
+    IOobjectOption::readOption readOpt
 )
 {
-    const bool ok = dict.readEntry(keyword, *this, keyType::LITERAL, mandatory);
+    const bool ok = dict.readEntry(keyword, *this, keyType::LITERAL, readOpt);
 
     if (ok && !empty())
     {
diff --git a/src/OpenFOAM/expressions/exprString/exprString.H b/src/OpenFOAM/expressions/exprString/exprString.H
index 0fc172070c..49957be0e2 100644
--- a/src/OpenFOAM/expressions/exprString/exprString.H
+++ b/src/OpenFOAM/expressions/exprString/exprString.H
@@ -175,7 +175,7 @@ public:
         (
             const word& keyword,  //!< Lookup key. Uses LITERAL (not REGEX)
             const dictionary& dict,
-            bool mandatory = true
+            IOobjectOption::readOption readOpt = IOobjectOption::MUST_READ
         );
 
         //- Read/expand optional entry with dictionary variables,
diff --git a/src/OpenFOAM/expressions/exprString/exprStringI.H b/src/OpenFOAM/expressions/exprString/exprStringI.H
index c0129e5b54..8218d709f6 100644
--- a/src/OpenFOAM/expressions/exprString/exprStringI.H
+++ b/src/OpenFOAM/expressions/exprString/exprStringI.H
@@ -195,7 +195,7 @@ inline bool Foam::expressions::exprString::readIfPresent
     const dictionary& dict
 )
 {
-    return readEntry(key, dict, false);  // non-mandatory
+    return readEntry(key, dict, IOobjectOption::READ_IF_PRESENT);
 }
 
 
diff --git a/src/OpenFOAM/global/argList/argList.C b/src/OpenFOAM/global/argList/argList.C
index 4a766fe4e2..d4e53691aa 100644
--- a/src/OpenFOAM/global/argList/argList.C
+++ b/src/OpenFOAM/global/argList/argList.C
@@ -1373,12 +1373,17 @@ void Foam::argList::parse
 
                 if (dictStream && dictStream->good())
                 {
+                    // Get numberOfSubdomains if it exists.
+                    // - mandatory when running with distributed roots
+
+                    IOobjectOption::readOption nDomainsReadOpt
+                        = IOobjectOption::READ_IF_PRESENT;
+
                     dictionary decompDict(*dictStream);
-                    bool nDomainsMandatory = false;
 
                     if (decompDict.getOrDefault("distributed", false))
                     {
-                        nDomainsMandatory = true;
+                        nDomainsReadOpt = IOobjectOption::MUST_READ;
                         runControl_.distributed(true);
                         decompDict.readEntry("roots", roots);
 
@@ -1390,14 +1395,12 @@ void Foam::argList::parse
                         }
                     }
 
-                    // Get numberOfSubdomains if it exists.
-                    // - mandatory when running with distributed roots
                     decompDict.readEntry
                     (
                         "numberOfSubdomains",
                         dictNProcs,
                         keyType::LITERAL,
-                        nDomainsMandatory
+                        nDomainsReadOpt
                     );
                 }
                 else
diff --git a/src/OpenFOAM/primitives/functions/Function1/Function1/Function1New.C b/src/OpenFOAM/primitives/functions/Function1/Function1/Function1New.C
index 6b60839e00..b5be2d0a1e 100644
--- a/src/OpenFOAM/primitives/functions/Function1/Function1/Function1New.C
+++ b/src/OpenFOAM/primitives/functions/Function1/Function1/Function1New.C
@@ -54,12 +54,16 @@ Foam::Function1<Type>::New
             << "For " << entryName << " with dictionary entries: "
             << flatOutput(coeffs->toc()) << nl;
 
+        // The "type" entry - mandatory if no redirectType provided
         coeffs->readEntry
         (
             "type",
             modelType,
             keyType::LITERAL,
-            modelType.empty()  // "type" entry is mandatory if no 'redirect'
+            (
+                modelType.empty()
+              ? IOobjectOption::MUST_READ : IOobjectOption::READ_IF_PRESENT
+            )
         );
 
         // Fallthrough
diff --git a/src/dynamicMesh/motionSmoother/motionSmootherAlgoTemplates.C b/src/dynamicMesh/motionSmoother/motionSmootherAlgoTemplates.C
index 0bb71f9110..496bf281d1 100644
--- a/src/dynamicMesh/motionSmoother/motionSmootherAlgoTemplates.C
+++ b/src/dynamicMesh/motionSmoother/motionSmootherAlgoTemplates.C
@@ -300,18 +300,16 @@ Type Foam::motionSmootherAlgo::get
     const Type& defaultValue
 )
 {
+    // If noExit, emit FatalIOError message without exiting
+    IOobjectOption::readOption readOpt
+    (
+        noExit
+      ? IOobjectOption::READ_IF_PRESENT : IOobjectOption::MUST_READ
+    );
+
     Type val(defaultValue);
 
-    if
-    (
-       !dict.readEntry
-        (
-            keyword,
-            val,
-            matchOpt,
-            !noExit
-        )
-    )
+    if (!dict.readEntry(keyword, val, matchOpt, readOpt))
     {
         FatalIOError
             << "Entry '" << keyword << "' not found in dictionary "
diff --git a/src/finiteVolume/fvMesh/wallDist/patchDistMethods/patchDistMethod/patchDistMethod.C b/src/finiteVolume/fvMesh/wallDist/patchDistMethods/patchDistMethod/patchDistMethod.C
index f656529c11..f3dcf1e85b 100644
--- a/src/finiteVolume/fvMesh/wallDist/patchDistMethods/patchDistMethod/patchDistMethod.C
+++ b/src/finiteVolume/fvMesh/wallDist/patchDistMethods/patchDistMethod/patchDistMethod.C
@@ -62,12 +62,17 @@ Foam::patchDistMethod::New
 )
 {
     word modelType(defaultPatchDistMethod);
+
+    // The "method" entry - mandatory if no default was provided
     dict.readEntry
     (
         "method",
         modelType,
-        keyType::REGEX,
-        modelType.empty()  // Mandatory if no default was provided
+        keyType::LITERAL,
+        (
+            modelType.empty()
+          ? IOobjectOption::MUST_READ : IOobjectOption::READ_IF_PRESENT
+        )
     );
 
     Info<< "Selecting patchDistMethod " << modelType << endl;
diff --git a/src/functionObjects/field/fieldValues/surfaceFieldValue/surfaceFieldValue.C b/src/functionObjects/field/fieldValues/surfaceFieldValue/surfaceFieldValue.C
index 5e422e52ef..11c1960245 100644
--- a/src/functionObjects/field/fieldValues/surfaceFieldValue/surfaceFieldValue.C
+++ b/src/functionObjects/field/fieldValues/surfaceFieldValue/surfaceFieldValue.C
@@ -1038,13 +1038,17 @@ bool Foam::functionObjects::fieldValues::surfaceFieldValue::read
             }
         }
 
-        // Mandatory if we didn't pick up a value from selectionNames_
+        // The "name" entry
+        // - mandatory if we didn't pick up a value from selectionNames_
         dict.readEntry
         (
             "name",
             regionName_,
             keyType::LITERAL,
-            regionName_.empty()
+            (
+                regionName_.empty()
+              ? IOobjectOption::MUST_READ : IOobjectOption::READ_IF_PRESENT
+            )
         );
 
         // Ensure there is always content for selectionNames_
diff --git a/src/mesh/snappyHexMesh/externalDisplacementMeshMover/medialAxisMeshMover.C b/src/mesh/snappyHexMesh/externalDisplacementMeshMover/medialAxisMeshMover.C
index bda99d0c86..97e67f7553 100644
--- a/src/mesh/snappyHexMesh/externalDisplacementMeshMover/medialAxisMeshMover.C
+++ b/src/mesh/snappyHexMesh/externalDisplacementMeshMover/medialAxisMeshMover.C
@@ -148,26 +148,15 @@ void Foam::medialAxisMeshMover::update(const dictionary& coeffDict)
         )
     );
 
-    // Note: parameter name changed
-    // "minMedianAxisAngle" -> "minMedialAxisAngle" (DEC-2013)
-    // but not previously reported.
-    scalar minMedialAxisAngle(Zero);
-    if
+    const scalar minMedialAxisAngle
     (
-       !coeffDict.readCompat
+        meshRefinement::get<scalar>
         (
+            coeffDict,
             "minMedialAxisAngle",
-            {{ "minMedianAxisAngle", 1712 }},
-            minMedialAxisAngle,
-            keyType::REGEX,
-            !dryRun_
+            dryRun_
         )
-    )
-    {
-        FatalIOError
-            << "Entry '" << "minMedialAxisAngle"
-            << "' not found in dictionary " << coeffDict.name() << endl;
-    }
+    );
 
     const scalar minMedialAxisAngleCos(Foam::cos(degToRad(minMedialAxisAngle)));
 
diff --git a/src/mesh/snappyHexMesh/meshRefinement/meshRefinement.C b/src/mesh/snappyHexMesh/meshRefinement/meshRefinement.C
index de014919c6..7e8ed9e187 100644
--- a/src/mesh/snappyHexMesh/meshRefinement/meshRefinement.C
+++ b/src/mesh/snappyHexMesh/meshRefinement/meshRefinement.C
@@ -3803,7 +3803,7 @@ const Foam::dictionary& Foam::meshRefinement::subDict
         auto& err = FatalIOErrorInFunction(dict);
 
         err << "Entry '" << keyword << "' not found in dictionary "
-            << dict.name() << nl;
+            << dict.relativeName() << nl;
 
         if (noExit)
         {
@@ -3827,14 +3827,14 @@ Foam::ITstream& Foam::meshRefinement::lookup
     enum keyType::option matchOpt
 )
 {
-    const auto finder(dict.csearch(keyword, matchOpt));
+    const entry* eptr = dict.findEntry(keyword, matchOpt);
 
-    if (!finder.good())
+    if (!eptr)
     {
         auto& err = FatalIOErrorInFunction(dict);
 
         err << "Entry '" << keyword << "' not found in dictionary "
-            << dict.name() << nl;
+            << dict.relativeName() << nl;
 
         if (noExit)
         {
@@ -3847,7 +3847,7 @@ Foam::ITstream& Foam::meshRefinement::lookup
         }
     }
 
-    return finder.ref().stream();
+    return eptr->stream();
 }
 
 
diff --git a/src/mesh/snappyHexMesh/meshRefinement/meshRefinementTemplates.C b/src/mesh/snappyHexMesh/meshRefinement/meshRefinementTemplates.C
index 580effaa02..f28ba6d468 100644
--- a/src/mesh/snappyHexMesh/meshRefinement/meshRefinementTemplates.C
+++ b/src/mesh/snappyHexMesh/meshRefinement/meshRefinementTemplates.C
@@ -335,9 +335,16 @@ Type Foam::meshRefinement::get
     const Type& deflt
 )
 {
+    // If noExit, emit FatalIOError message without exiting
+    IOobjectOption::readOption readOpt
+    (
+        noExit
+      ? IOobjectOption::READ_IF_PRESENT : IOobjectOption::MUST_READ
+    );
+
     Type val(deflt);
 
-    if (!dict.readEntry(keyword, val, matchOpt, !noExit))
+    if (!dict.readEntry(keyword, val, matchOpt, readOpt))
     {
         FatalIOErrorInFunction(dict)
             << "Entry '" << keyword << "' not found in dictionary "
diff --git a/src/meshTools/PatchFunction1/PatchFunction1/PatchFunction1New.C b/src/meshTools/PatchFunction1/PatchFunction1/PatchFunction1New.C
index f371329280..d664cd71ea 100644
--- a/src/meshTools/PatchFunction1/PatchFunction1/PatchFunction1New.C
+++ b/src/meshTools/PatchFunction1/PatchFunction1/PatchFunction1New.C
@@ -53,12 +53,13 @@ Foam::PatchFunction1<Type>::New
             << "For " << entryName << " with dictionary entries: "
             << flatOutput(coeffs->toc()) << nl;
 
+        // The "type" entry - mandatory, no fallback type provided
         coeffs->readEntry
         (
             "type",
             modelType,
-            keyType::LITERAL
-            // "type" entry is mandatory, there is no 'redirect'
+            keyType::LITERAL,
+            IOobjectOption::MUST_READ
         );
     }
     else if (eptr)
diff --git a/src/meshTools/searchableSurfaces/searchableBox/searchableBox.C b/src/meshTools/searchableSurfaces/searchableBox/searchableBox.C
index ec4045a731..015ce5d8a0 100644
--- a/src/meshTools/searchableSurfaces/searchableBox/searchableBox.C
+++ b/src/meshTools/searchableSurfaces/searchableBox/searchableBox.C
@@ -59,13 +59,17 @@ namespace Foam
 // Read min/max or min/span
 static void readBoxDim(const dictionary& dict, treeBoundBox& bb)
 {
-    dict.readEntry<point>("min", bb.min());
+    IOobjectOption::readOption readOpt = IOobjectOption::MUST_READ;
 
-    const bool hasSpan = dict.found("span");
-    if (!dict.readEntry<point>("max", bb.max(), keyType::REGEX, !hasSpan))
+    dict.readEntry("min", bb.min(), keyType::LITERAL, readOpt);
+
+    if (dict.readIfPresent("span", bb.max(), keyType::LITERAL))
     {
-        bb.max() = bb.min() + dict.get<vector>("span");
+        bb.max() += bb.min();
+        readOpt = IOobjectOption::READ_IF_PRESENT;
     }
+
+    dict.readEntry("max", bb.max(), keyType::LITERAL, readOpt);
 }
 
 } // End namespace Foam
diff --git a/src/meshTools/topoSet/cellSources/boxToCell/boxToCell.C b/src/meshTools/topoSet/cellSources/boxToCell/boxToCell.C
index 62d0228a8f..a3ca126907 100644
--- a/src/meshTools/topoSet/cellSources/boxToCell/boxToCell.C
+++ b/src/meshTools/topoSet/cellSources/boxToCell/boxToCell.C
@@ -72,13 +72,17 @@ namespace Foam
 // Read min/max or min/span
 static void readBoxDim(const dictionary& dict, treeBoundBox& bb)
 {
-    dict.readEntry<point>("min", bb.min());
+    IOobjectOption::readOption readOpt = IOobjectOption::MUST_READ;
 
-    const bool hasSpan = dict.found("span");
-    if (!dict.readEntry<point>("max", bb.max(), keyType::REGEX, !hasSpan))
+    dict.readEntry("min", bb.min(), keyType::LITERAL, readOpt);
+
+    if (dict.readIfPresent("span", bb.max(), keyType::LITERAL))
     {
-        bb.max() = bb.min() + dict.get<vector>("span");
+        bb.max() += bb.min();
+        readOpt = IOobjectOption::READ_IF_PRESENT;
     }
+
+    dict.readEntry("max", bb.max(), keyType::LITERAL, readOpt);
 }
 
 } // End namespace Foam
diff --git a/src/meshTools/topoSet/faceSources/boxToFace/boxToFace.C b/src/meshTools/topoSet/faceSources/boxToFace/boxToFace.C
index 38feb4948a..91b633d13c 100644
--- a/src/meshTools/topoSet/faceSources/boxToFace/boxToFace.C
+++ b/src/meshTools/topoSet/faceSources/boxToFace/boxToFace.C
@@ -72,13 +72,17 @@ namespace Foam
 // Read min/max or min/span
 static void readBoxDim(const dictionary& dict, treeBoundBox& bb)
 {
-    dict.readEntry<point>("min", bb.min());
+    IOobjectOption::readOption readOpt = IOobjectOption::MUST_READ;
 
-    const bool hasSpan = dict.found("span");
-    if (!dict.readEntry<point>("max", bb.max(), keyType::REGEX, !hasSpan))
+    dict.readEntry("min", bb.min(), keyType::LITERAL, readOpt);
+
+    if (dict.readIfPresent("span", bb.max(), keyType::LITERAL))
     {
-        bb.max() = bb.min() + dict.get<vector>("span");
+        bb.max() += bb.min();
+        readOpt = IOobjectOption::READ_IF_PRESENT;
     }
+
+    dict.readEntry("max", bb.max(), keyType::LITERAL, readOpt);
 }
 
 } // End namespace Foam
diff --git a/src/meshTools/topoSet/pointSources/boxToPoint/boxToPoint.C b/src/meshTools/topoSet/pointSources/boxToPoint/boxToPoint.C
index 6dcb58e141..9086bb4098 100644
--- a/src/meshTools/topoSet/pointSources/boxToPoint/boxToPoint.C
+++ b/src/meshTools/topoSet/pointSources/boxToPoint/boxToPoint.C
@@ -72,13 +72,17 @@ namespace Foam
 // Read min/max or min/span
 static void readBoxDim(const dictionary& dict, treeBoundBox& bb)
 {
-    dict.readEntry<point>("min", bb.min());
+    IOobjectOption::readOption readOpt = IOobjectOption::MUST_READ;
 
-    const bool hasSpan = dict.found("span");
-    if (!dict.readEntry<point>("max", bb.max(), keyType::REGEX, !hasSpan))
+    dict.readEntry("min", bb.min(), keyType::LITERAL, readOpt);
+
+    if (dict.readIfPresent("span", bb.max(), keyType::LITERAL))
     {
-        bb.max() = bb.min() + dict.get<vector>("span");
+        bb.max() += bb.min();
+        readOpt = IOobjectOption::READ_IF_PRESENT;
     }
+
+    dict.readEntry("max", bb.max(), keyType::LITERAL, readOpt);
 }
 
 } // End namespace Foam