diff --git a/src/ArduinoCompat/Client.h b/src/ArduinoCompat/Client.h
index e0c85de..0421b30 100644
--- a/src/ArduinoCompat/Client.h
+++ b/src/ArduinoCompat/Client.h
@@ -24,22 +24,24 @@
 #include "ArduinoCompat/IPAddress.h"
 
 class Client : public Stream {
+ public:
+  virtual int     connect(IPAddress ip, uint16_t port)     = 0;
+  virtual int     connect(const char* host, uint16_t port) = 0;
+  virtual size_t  write(uint8_t)                           = 0;
+  virtual size_t  write(const uint8_t* buf, size_t size)   = 0;
+  virtual int     available()                              = 0;
+  virtual int     read()                                   = 0;
+  virtual int     read(uint8_t* buf, size_t size)          = 0;
+  virtual int     peek()                                   = 0;
+  virtual void    flush()                                  = 0;
+  virtual void    stop()                                   = 0;
+  virtual uint8_t connected()                              = 0;
+  virtual         operator bool()                          = 0;
 
-public:
-  virtual int connect(IPAddress ip, uint16_t port) =0;
-  virtual int connect(const char *host, uint16_t port) =0;
-  virtual size_t write(uint8_t) =0;
-  virtual size_t write(const uint8_t *buf, size_t size) =0;
-  virtual int available() = 0;
-  virtual int read() = 0;
-  virtual int read(uint8_t *buf, size_t size) = 0;
-  virtual int peek() = 0;
-  virtual void flush() = 0;
-  virtual void stop() = 0;
-  virtual uint8_t connected() = 0;
-  virtual operator bool() = 0;
-protected:
-  uint8_t* rawIPAddress(IPAddress& addr) { return addr.raw_address(); };
+ protected:
+  uint8_t* rawIPAddress(IPAddress& addr) {
+    return addr.raw_address();
+  };
 };
 
 #endif
diff --git a/src/TinyGsmClientA6.h b/src/TinyGsmClientA6.h
index cc6f946..9226960 100644
--- a/src/TinyGsmClientA6.h
+++ b/src/TinyGsmClientA6.h
@@ -79,7 +79,7 @@ class TinyGsmA6 : public TinyGsmModem<TinyGsmA6>,
     }
 
    public:
-    int connect(const char* host, uint16_t port, int timeout_s) {
+    virtual int connect(const char* host, uint16_t port, int timeout_s) {
       stop();
       TINY_GSM_YIELD();
       rx.clear();
diff --git a/src/TinyGsmClientM590.h b/src/TinyGsmClientM590.h
index 43804e2..e921447 100644
--- a/src/TinyGsmClientM590.h
+++ b/src/TinyGsmClientM590.h
@@ -79,7 +79,7 @@ class TinyGsmM590 : public TinyGsmModem<TinyGsmM590>,
     }
 
    public:
-    int connect(const char* host, uint16_t port, int timeout_s) {
+    virtual int connect(const char* host, uint16_t port, int timeout_s) {
       stop();
       TINY_GSM_YIELD();
       rx.clear();
diff --git a/src/TinyGsmNTP.tpp b/src/TinyGsmNTP.tpp
index be8ff4e..aaeda7e 100644
--- a/src/TinyGsmNTP.tpp
+++ b/src/TinyGsmNTP.tpp
@@ -21,7 +21,7 @@ class TinyGsmNTP {
    */
 
  public:
-  boolean TinyGsmIsValidNumber(String str) {
+  bool TinyGsmIsValidNumber(String str) {
     if (!(str.charAt(0) == '+' || str.charAt(0) == '-' ||
           isDigit(str.charAt(0))))
       return false;