diff --git a/slsDetectorServers/gotthard2DetectorServer/bin/gotthard2DetectorServer_developer b/slsDetectorServers/gotthard2DetectorServer/bin/gotthard2DetectorServer_developer
index 431f88bc9..b70ab78ae 100755
Binary files a/slsDetectorServers/gotthard2DetectorServer/bin/gotthard2DetectorServer_developer and b/slsDetectorServers/gotthard2DetectorServer/bin/gotthard2DetectorServer_developer differ
diff --git a/slsDetectorServers/slsDetectorServer/include/LTC2620_Driver.h b/slsDetectorServers/slsDetectorServer/include/LTC2620_Driver.h
index 1a5c07e8a..34435c9bb 100644
--- a/slsDetectorServers/slsDetectorServer/include/LTC2620_Driver.h
+++ b/slsDetectorServers/slsDetectorServer/include/LTC2620_Driver.h
@@ -31,7 +31,8 @@ int LTC2620_D_DacToVoltage(int dacval, int *voltage);
 int LTC2620_D_WriteDACValue(int dacnum, int dacvalue, char *dacname);
 
 /**
- * Set value for dac only
+ * Only for DACs (not power regulators) to validate indices and convert values
+ * to dac units if needed
  * @param dacval if val is in mV, returns dac units set
  */
 int LTC2620_D_SetDACValue(int dacnum, int val, int mV, char *dacname,
diff --git a/slsDetectorServers/slsDetectorServer/src/LTC2620_Driver.c b/slsDetectorServers/slsDetectorServer/src/LTC2620_Driver.c
index 3da1acd66..8add1b10a 100644
--- a/slsDetectorServers/slsDetectorServer/src/LTC2620_Driver.c
+++ b/slsDetectorServers/slsDetectorServer/src/LTC2620_Driver.c
@@ -4,7 +4,7 @@
 #include "clogger.h"
 #include "common.h"
 
-// to include power down file name suffix
+// to include power down file name suffix directly
 #ifdef XILINX_CHIPTESTBOARDD
 #include "slsDetectorServer_defs.h"
 #else
@@ -70,13 +70,24 @@ int LTC2620_D_WriteDACValue(int dacnum, int dacvalue, char *dacname) {
         return FAIL;
     }
 
-    // validate value
-    if ((dacvalue < 0 && dacvalue != LTC2620_D_PWR_DOWN_VAL) ||
-        (dacvalue > LTC2620_D_MAX_DAC_VAL)) {
+    // validate max value
+    if (dacvalue > LTC2620_D_MAX_DAC_VAL) {
         LOG(logERROR,
             ("Dac %d %s: Invalid dac value %d\n", dacnum, dacname, dacvalue));
         return FAIL;
     }
+    // validate negative values
+    if (dacvalue < 0) {
+        // dacs only: allow power down value (-100)
+        if ((dacnum < LTC2620_D_NumDacsOnly &&
+             dacvalue != LTC2620_D_PWR_DOWN_VAL) ||
+            // power regulators: allow no negative values
+            (dacnum >= LTC2620_D_NumDacsOnly)) {
+            LOG(logERROR, ("Dac %d %s: Invalid dac value %d\n", dacnum, dacname,
+                           dacvalue));
+            return FAIL;
+        }
+    }
 
     // print info
     if (dacvalue == LTC2620_D_PWR_DOWN_VAL) {
diff --git a/slsDetectorServers/xilinx_ctbDetectorServer/bin/xilinx_ctbDetectorServer_developer b/slsDetectorServers/xilinx_ctbDetectorServer/bin/xilinx_ctbDetectorServer_developer
index 05dd2a06b..61d8da984 100755
Binary files a/slsDetectorServers/xilinx_ctbDetectorServer/bin/xilinx_ctbDetectorServer_developer and b/slsDetectorServers/xilinx_ctbDetectorServer/bin/xilinx_ctbDetectorServer_developer differ
diff --git a/slsSupportLib/include/sls/versionAPI.h b/slsSupportLib/include/sls/versionAPI.h
index 71ed7af12..3e230eece 100644
--- a/slsSupportLib/include/sls/versionAPI.h
+++ b/slsSupportLib/include/sls/versionAPI.h
@@ -4,7 +4,7 @@
 #define APILIB       "0.0.0 0x250909"
 #define APIRECEIVER  "0.0.0 0x250822"
 #define APICTB       "0.0.0 0x250922"
-#define APIGOTTHARD2 "0.0.0 0x260113"
+#define APIGOTTHARD2 "0.0.0 0x260114"
 #define APIMOENCH    "0.0.0 0x250909"
 #define APIEIGER     "0.0.0 0x250909"
 #define APIXILINXCTB "0.0.0 0x260114"