diff --git a/Telegram/SourceFiles/config.h.in b/Telegram/SourceFiles/config.h.in
index 79865ec13..00ddc6153 100644
--- a/Telegram/SourceFiles/config.h.in
+++ b/Telegram/SourceFiles/config.h.in
@@ -169,7 +169,7 @@ inline const char *cGUIDStr() {
 	return gGuidStr;
 }
 
-inline const char **cPublicRSAKeys(int &keysCount) {
+inline const char **cPublicRSAKeys(size_t &keysCount) {
 	static const char *(keys[]) = {"\
 -----BEGIN RSA PUBLIC KEY-----\n\
 MIIBCgKCAQEAwVACPi9w23mF3tBkdZz+zwrzKOaaQdr01vAbU4E1pvkfj4sqDsm6\n\
diff --git a/Telegram/SourceFiles/mtproto/core_types.h b/Telegram/SourceFiles/mtproto/core_types.h
index b79931060..58ea7e58a 100644
--- a/Telegram/SourceFiles/mtproto/core_types.h
+++ b/Telegram/SourceFiles/mtproto/core_types.h
@@ -587,13 +587,13 @@ using MTPString = MTPBoxed<MTPstring>;
 using MTPBytes = MTPBoxed<MTPbytes>;
 
 inline MTPstring MTP_string(const std::string &v) {
-	return MTPstring(QByteArray(v.data(), v.size()));
+	return MTPstring(QByteArray(v.data(), static_cast<int>(v.size())));
 }
 inline MTPstring MTP_string(const QString &v) {
 	return MTPstring(v.toUtf8());
 }
 inline MTPstring MTP_string(const char *v) {
-	return MTPstring(QByteArray(v, strlen(v)));
+	return MTPstring(QByteArray(v, static_cast<int>(strlen(v))));
 }
 MTPstring MTP_string(const QByteArray &v) = delete;
 
@@ -604,7 +604,7 @@ inline MTPbytes MTP_bytes(QByteArray &&v) {
 	return MTPbytes(std::move(v));
 }
 inline MTPbytes MTP_bytes(base::const_byte_span bytes) {
-	return MTP_bytes(QByteArray(reinterpret_cast<const char *>(bytes.data()), bytes.size()));
+	return MTP_bytes(QByteArray(reinterpret_cast<const char *>(bytes.data()), static_cast<int>(bytes.size())));
 }
 inline MTPbytes MTP_bytes(const std::vector<gsl::byte> &bytes) {
 	return MTP_bytes(gsl::make_span(bytes));
@@ -714,7 +714,7 @@ struct MTPStringLogger {
 	}
 
 	MTPStringLogger &add(const char *data, qint32 len = -1) {
-		if (len < 0) len = strlen(data);
+		if (len < 0) len = static_cast<qint32>(strlen(data));
 		if (!len) return (*this);
 
 		ensureLength(len);
diff --git a/Telegram/SourceFiles/mtproto/dc_options.cpp b/Telegram/SourceFiles/mtproto/dc_options.cpp
index 1299a0ba7..0884333ef 100644
--- a/Telegram/SourceFiles/mtproto/dc_options.cpp
+++ b/Telegram/SourceFiles/mtproto/dc_options.cpp
@@ -53,9 +53,9 @@ private:
 };
 
 void DcOptions::readBuiltInPublicKeys() {
-	auto keysCount = 0;
+	size_t keysCount = 0;
 	auto keys = cPublicRSAKeys(keysCount);
-	for (auto i = 0; i != keysCount; ++i) {
+	for (size_t i = 0; i != keysCount; ++i) {
 		auto keyBytes = gsl::as_bytes(gsl::make_span(keys[i], keys[i] + strlen(keys[i])));
 		auto key = internal::RSAPublicKey(keyBytes);
 		if (key.isValid()) {