diff --git a/src/TinyGsmClientXBee.h b/src/TinyGsmClientXBee.h
index f553f54..deba450 100644
--- a/src/TinyGsmClientXBee.h
+++ b/src/TinyGsmClientXBee.h
@@ -836,6 +836,10 @@ class TinyGsmXBee
     return sendATGetString(GF("IM"));
   }
 
+  String getIMSIImpl() {
+    return sendATGetString(GF("II"));
+  }
+
   SimStatus getSimStatusImpl(uint32_t) {
     return SIM_READY;  // unsupported
   }
diff --git a/src/TinyGsmCommon.h b/src/TinyGsmCommon.h
index 6efc403..683795b 100644
--- a/src/TinyGsmCommon.h
+++ b/src/TinyGsmCommon.h
@@ -117,18 +117,3 @@ uint32_t TinyGsmAutoBaud(T& SerialAT, uint32_t minimum = 9600,
 }
 
 #endif  // SRC_TINYGSMCOMMON_H_
-
-// Asks for International Mobile Subscriber Identity IMSI via the AT+CIMI command
-#define TINY_GSM_MODEM_GET_IMSI_CIMI() \
-  String getIMSI() { \
-    sendAT(GF("+CIMI")); \
-    if (waitResponse(GF(GSM_NL)) != 1) { \
-      return ""; \
-    } \
-    String res = stream.readStringUntil('\n'); \
-    waitResponse(); \
-    res.trim(); \
-    return res; \
-  }
-
-
diff --git a/src/TinyGsmGPRS.tpp b/src/TinyGsmGPRS.tpp
index 00bf1b7..7a08598 100644
--- a/src/TinyGsmGPRS.tpp
+++ b/src/TinyGsmGPRS.tpp
@@ -38,6 +38,10 @@ class TinyGsmGPRS {
   String getIMEI() {
     return thisModem().getIMEIImpl();
   }
+  // Asks for International Mobile Subscriber Identity IMSI
+  String getIMSI() {
+    return thisModem().getIMSIImpl();
+  }
   SimStatus getSimStatus(uint32_t timeout_ms = 10000L) {
     return thisModem().getSimStatusImpl(timeout_ms);
   }
@@ -105,6 +109,16 @@ class TinyGsmGPRS {
     return res;
   }
 
+  // Asks for International Mobile Subscriber Identity IMSI via the AT+CIMI
+  // command
+  String getIMSIImpl() {
+    thisModem().sendAT(GF("+CIMI"));
+    String res = thisModem().stream.readStringUntil('\n');
+    thisModem().waitResponse();
+    res.trim();
+    return res;
+  }
+
   SimStatus getSimStatusImpl(uint32_t timeout_ms = 10000L) {
     for (uint32_t start = millis(); millis() - start < timeout_ms;) {
       thisModem().sendAT(GF("+CPIN?"));