diff --git a/rehlds/engine/APIProxy.h b/rehlds/engine/APIProxy.h
index 0ac2dcb..15c4c26 100644
--- a/rehlds/engine/APIProxy.h
+++ b/rehlds/engine/APIProxy.h
@@ -576,7 +576,7 @@ typedef void(*pfnEngDst_pfnGetScreenFade_t)						(struct screenfade_s **);
 typedef void(*pfnEngDst_pfnSetScreenFade_t)						(struct screenfade_s **);
 typedef void(*pfnEngDst_VGui_GetPanel_t)						();
 typedef void(*pfnEngDst_VGui_ViewportPaintBackground_t)			(int **);
-typedef void(*pfnEngDst_COM_LoadFile_t)							(char **, int *, int **);
+typedef void(*pfnEngDst_COM_LoadFile_t)							(const char **, int *, int **);
 typedef void(*pfnEngDst_COM_ParseFile_t)						(char **, char **);
 typedef void(*pfnEngDst_COM_FreeFile_t)							(void **);
 typedef void(*pfnEngDst_IsSpectateOnly_t)						(void);
diff --git a/rehlds/engine/common.cpp b/rehlds/engine/common.cpp
index 4b36514..169b688 100644
--- a/rehlds/engine/common.cpp
+++ b/rehlds/engine/common.cpp
@@ -1973,7 +1973,7 @@ NOXREF int COM_ExpandFilename(char *filename)
 	return *filename != 0;
 }
 
-int EXT_FUNC COM_FileSize(char *filename)
+int EXT_FUNC COM_FileSize(const char *filename)
 {
 	FileHandle_t fp;
 	int iSize;
@@ -2385,7 +2385,7 @@ void COM_Log(char *pszFile, char *fmt, ...)
 	}
 }
 
-unsigned char* EXT_FUNC COM_LoadFileForMe(char *filename, int *pLength)
+unsigned char* EXT_FUNC COM_LoadFileForMe(const char *filename, int *pLength)
 {
 	return COM_LoadFile(filename, 5, pLength);
 }
diff --git a/rehlds/engine/common.h b/rehlds/engine/common.h
index 3ea8174..6c30045 100644
--- a/rehlds/engine/common.h
+++ b/rehlds/engine/common.h
@@ -317,7 +317,7 @@ void COM_FixSlashes(char *pname);
 void COM_CreatePath(char *path);
 NOXREF void COM_CopyFile(char *netpath, char *cachepath);
 NOXREF int COM_ExpandFilename(char *filename);
-int COM_FileSize(char *filename);
+int COM_FileSize(const char *filename);
 unsigned char *COM_LoadFile(const char *path, int usehunk, int *pLength);
 void COM_FreeFile(void *buffer);
 void COM_CopyFileChunk(FileHandle_t dst, FileHandle_t src, int nSize);
@@ -335,7 +335,7 @@ qboolean COM_SetupDirectories(void);
 void COM_CheckPrintMap(dheader_t *header, const char *mapname, qboolean bShowOutdated);
 void COM_ListMaps(char *pszSubString);
 void COM_Log(char *pszFile, char *fmt, ...);
-unsigned char *COM_LoadFileForMe(char *filename, int *pLength);
+unsigned char *COM_LoadFileForMe(const char *filename, int *pLength);
 int COM_CompareFileTime(char *filename1, char *filename2, int *iCompare);
 void COM_GetGameDir(char *szGameDir);
 int COM_EntsForPlayerSlots(int nPlayers);
diff --git a/rehlds/engine/delta.cpp b/rehlds/engine/delta.cpp
index d6f029d..6b242e6 100644
--- a/rehlds/engine/delta.cpp
+++ b/rehlds/engine/delta.cpp
@@ -993,7 +993,7 @@ int DELTA_ParseDelta(unsigned char *from, unsigned char *to, delta_t *pFields)
 	return MSG_CurrentBit() - startbit;
 }
 
-void EXT_FUNC DELTA_AddEncoder(char *name, void(*conditionalencode)(struct delta_s *, const unsigned char *, const unsigned char *))
+void EXT_FUNC DELTA_AddEncoder(const char *name, void(*conditionalencode)(struct delta_s *, const unsigned char *, const unsigned char *))
 {
 	delta_encoder_t *p = (delta_encoder_t *)Mem_ZeroMalloc(sizeof(delta_encoder_t));
 	p->name = Mem_Strdup(name);
diff --git a/rehlds/engine/delta.h b/rehlds/engine/delta.h
index 92b439e..953530e 100644
--- a/rehlds/engine/delta.h
+++ b/rehlds/engine/delta.h
@@ -136,7 +136,7 @@ qboolean DELTA_WriteDeltaForceMask(unsigned char *from, unsigned char *to, qbool
 qboolean DELTA_WriteDelta(unsigned char *from, unsigned char *to, qboolean force, delta_t *pFields, void(*callback)(void));
 qboolean _DELTA_WriteDelta(unsigned char *from, unsigned char *to, qboolean force, delta_t *pFields, void(*callback)(void), qboolean sendfields);
 int DELTA_ParseDelta(unsigned char *from, unsigned char *to, delta_t *pFields);
-void DELTA_AddEncoder(char *name, void(*conditionalencode)(struct delta_s *, const unsigned char *, const unsigned char *));
+void DELTA_AddEncoder(const char *name, void(*conditionalencode)(struct delta_s *, const unsigned char *, const unsigned char *));
 void DELTA_ClearEncoders(void);
 encoder_t DELTA_LookupEncoder(char *name);
 int DELTA_CountLinks(delta_link_t *plinks);
diff --git a/rehlds/engine/pr_cmds.cpp b/rehlds/engine/pr_cmds.cpp
index ba88336..74936c5 100644
--- a/rehlds/engine/pr_cmds.cpp
+++ b/rehlds/engine/pr_cmds.cpp
@@ -816,7 +816,7 @@ qboolean EXT_FUNC ValidCmd(const char *pCmd)
 	return len && (pCmd[len - 1] == '\n' || pCmd[len - 1] == ';');
 }
 
-void EXT_FUNC PF_stuffcmd_I(edict_t *pEdict, char *szFmt, ...)
+void EXT_FUNC PF_stuffcmd_I(edict_t *pEdict, const char *szFmt, ...)
 {
 	int entnum;
 	client_t *old;
@@ -850,7 +850,7 @@ void EXT_FUNC PF_stuffcmd_I(edict_t *pEdict, char *szFmt, ...)
 	}
 }
 
-void EXT_FUNC PF_localcmd_I(char *str)
+void EXT_FUNC PF_localcmd_I(const char *str)
 {
 	if (ValidCmd(str))
 		Cbuf_AddText(str);
@@ -1457,7 +1457,7 @@ int EXT_FUNC PF_precache_model_I(const char *s)
 }
 
 #ifdef REHLDS_FIXES
-int EXT_FUNC PF_precache_generic_I(char *s)
+int EXT_FUNC PF_precache_generic_I(const char *s)
 {
 	if (!s)
 		Host_Error("%s: NULL pointer", __func__);
@@ -1504,7 +1504,7 @@ int EXT_FUNC PF_precache_generic_I(char *s)
 	return g_rehlds_sv.precachedGenericResourceCount++;
 }
 #else // REHLDS_FIXES
-int EXT_FUNC PF_precache_generic_I(char *s)
+int EXT_FUNC PF_precache_generic_I(const char *s)
 {
 	if (!s)
 		Host_Error("%s: NULL pointer", __func__);
@@ -1544,7 +1544,7 @@ int EXT_FUNC PF_precache_generic_I(char *s)
 }
 #endif // REHLDS_FIXES
 
-int EXT_FUNC PF_IsMapValid_I(char *mapname)
+int EXT_FUNC PF_IsMapValid_I(const char *mapname)
 {
 	char cBuf[260];
 	if (!mapname || Q_strlen(mapname) == 0)
diff --git a/rehlds/engine/pr_cmds.h b/rehlds/engine/pr_cmds.h
index 553615f..e1a12f0 100644
--- a/rehlds/engine/pr_cmds.h
+++ b/rehlds/engine/pr_cmds.h
@@ -129,8 +129,8 @@ mnode_t *PVSNode(mnode_t *node, vec_t *emins, vec_t *emaxs);
 void PVSMark(model_t *pmodel, unsigned char *ppvs);
 edict_t *PVSFindEntities(edict_t *pplayer);
 qboolean ValidCmd(const char *pCmd);
-void PF_stuffcmd_I(edict_t *pEdict, char *szFmt, ...);
-void PF_localcmd_I(char *str);
+void PF_stuffcmd_I(edict_t *pEdict, const char *szFmt, ...);
+void PF_localcmd_I(const char *str);
 void PF_localexec_I(void);
 edict_t *FindEntityInSphere(edict_t *pEdictStartSearchAfter, const float *org, float rad);
 edict_t *PF_Spawn_I(void);
@@ -150,8 +150,8 @@ void EV_PlayReliableEvent_internal(client_t *cl, int entindex, unsigned short ev
 void EV_Playback(int flags, const edict_t *pInvoker, unsigned short eventindex, float delay, float *origin, float *angles, float fparam1, float fparam2, int iparam1, int iparam2, int bparam1, int bparam2);
 void EV_SV_Playback(int flags, int clientindex, unsigned short eventindex, float delay, float *origin, float *angles, float fparam1, float fparam2, int iparam1, int iparam2, int bparam1, int bparam2);
 int PF_precache_model_I(const char *s);
-int PF_precache_generic_I(char *s);
-int PF_IsMapValid_I(char *mapname);
+int PF_precache_generic_I(const char *s);
+int PF_IsMapValid_I(const char *mapname);
 int PF_NumberOfEntities_I(void);
 char *PF_GetInfoKeyBuffer_I(edict_t *e);
 char *PF_InfoKeyValue_I(char *infobuffer, const char *key);
diff --git a/rehlds/pm_shared/pm_defs.h b/rehlds/pm_shared/pm_defs.h
index 1a5f01d..7350c1a 100644
--- a/rehlds/pm_shared/pm_defs.h
+++ b/rehlds/pm_shared/pm_defs.h
@@ -208,7 +208,7 @@ typedef struct playermove_s
 	void			(*PM_GetModelBounds)( struct model_s *mod, float *mins, float *maxs );
 	void			*(*PM_HullForBsp)( physent_t *pe, float *offset );
 	float			(*PM_TraceModel)( physent_t *pEnt, float *start, float *end, trace_t *trace );
-	int				(*COM_FileSize)(char *filename);
+	int				(*COM_FileSize)(const char *filename);
 	byte			*(*COM_LoadFile) (const char *path, int usehunk, int *pLength);
 	void			(*COM_FreeFile) ( void *buffer );
 	char			*(*memfgets)( byte *pMemFile, int fileSize, int *pFilePos, char *pBuffer, int bufferSize );
diff --git a/rehlds/public/rehlds/eiface.h b/rehlds/public/rehlds/eiface.h
index b679719..f773e98 100644
--- a/rehlds/public/rehlds/eiface.h
+++ b/rehlds/public/rehlds/eiface.h
@@ -144,9 +144,9 @@ typedef struct enginefuncs_s
 	const char *(*pfnTraceTexture)			(edict_t *pTextureEntity, const float *v1, const float *v2 );
 	void		(*pfnTraceSphere)			(const float *v1, const float *v2, int fNoMonsters, float radius, edict_t *pentToSkip, TraceResult *ptr);
 	void		(*pfnGetAimVector)			(edict_t* ent, float speed, float *rgflReturn);
-	void		(*pfnServerCommand)			(char* str);
+	void		(*pfnServerCommand)			(const char* str);
 	void		(*pfnServerExecute)			(void);
-	void		(*pfnClientCommand)			(edict_t* pEdict, char* szFmt, ...);
+	void		(*pfnClientCommand)			(edict_t* pEdict, const char* szFmt, ...);
 	void		(*pfnParticleEffect)		(const float *org, const float *dir, float color, float count);
 	void		(*pfnLightStyle)			(int style, char* val);
 	int			(*pfnDecalIndex)			(const char *name);
@@ -200,7 +200,7 @@ typedef struct enginefuncs_s
 	void		(*pfnSetView)				(const edict_t *pClient, const edict_t *pViewent );
 	float		(*pfnTime)					( void );
 	void		(*pfnCrosshairAngle)		(const edict_t *pClient, float pitch, float yaw);
-	byte *      (*pfnLoadFileForMe)         (char *filename, int *pLength);
+	byte *      (*pfnLoadFileForMe)         (const char *filename, int *pLength);
 	void        (*pfnFreeFile)              (void *buffer);
 	void        (*pfnEndSection)            (const char *pszSectionName); // trigger_endsection
 	int 		(*pfnCompareFileTime)       (char *filename1, char *filename2, int *iCompare);
@@ -215,9 +215,9 @@ typedef struct enginefuncs_s
 	char*		(*pfnInfoKeyValue)			(char *infobuffer, const char *key);
 	void		(*pfnSetKeyValue)			(char *infobuffer, const char *key, const char *value);
 	void		(*pfnSetClientKeyValue)		(int clientIndex, char *infobuffer, const char *key, const char *value);
-	int			(*pfnIsMapValid)			(char *filename);
+	int			(*pfnIsMapValid)			(const char *filename);
 	void		(*pfnStaticDecal)			( const float *origin, int decalIndex, int entityIndex, int modelIndex );
-	int			(*pfnPrecacheGeneric)		(char* s);
+	int			(*pfnPrecacheGeneric)		(const char* s);
 	int			(*pfnGetPlayerUserId)		(edict_t *e ); // returns the server assigned userid for this player.  useful for logging frags, etc.  returns -1 if the edict couldn't be found in the list of clients
 	void		(*pfnBuildSoundMsg)			(edict_t *entity, int channel, const char *sample, /*int*/float volume, float attenuation, int fFlags, int pitch, int msg_dest, int msg_type, const float *pOrigin, edict_t *ed);
 	int			(*pfnIsDedicatedServer)		(void);// is this a dedicated server?
@@ -239,7 +239,7 @@ typedef struct enginefuncs_s
 
 	void		(*pfnDeltaSetField)			( struct delta_s *pFields, const char *fieldname );
 	void		(*pfnDeltaUnsetField)		( struct delta_s *pFields, const char *fieldname );
-	void		(*pfnDeltaAddEncoder)		( char *name, void (*conditionalencode)( struct delta_s *pFields, const unsigned char *from, const unsigned char *to ) );
+	void		(*pfnDeltaAddEncoder)		( const char *name, void (*conditionalencode)( struct delta_s *pFields, const unsigned char *from, const unsigned char *to ) );
 	int			(*pfnGetCurrentPlayer)		( void );
 	int			(*pfnCanSkipPlayer)			( const edict_t *player );
 	int			(*pfnDeltaFindField)		( struct delta_s *pFields, const char *fieldname );
@@ -274,7 +274,7 @@ typedef struct enginefuncs_s
 	sentenceEntry_s*	(*pfnSequencePickSentence)		( const char* groupName, int pickMethod, int *picked );
 
 	// LH: Give access to filesize via filesystem
-	int			(*pfnGetFileSize)						( char *filename );
+	int			(*pfnGetFileSize)						( const char *filename );
 
 	unsigned int (*pfnGetApproxWavePlayLen)				(const char *filepath);
 	// MDC: Added for CZ career-mode