Uncertain as to which programmers you refer to - details of those available follow below.
It is prudent,when buying second hand digital servos or swapping from one model to another, to test and reset each one to factory default before re-using them. There can never be any certainty as to what a previous user has input, even minor adjustments can cause problems in other models. Many users quickly forget which servo has or has not been reprogrammed.
HFP-10 Digital Servo Programmer FAQs
Digital Servo Instruction Videos - HFP-10 programming
An earlier product announcement New High Performance Digi Servos From Hitec . NB: All G2 premium digital servos are equipped with coreless motors and dual ball bearings.

Here is the comparison chart between the programmers and Hitec digital servos.
Servo Test & Programmable functions of old HFP-10 (Which can not be upgraded but may possibly be exchanged at a reduced cost subject to direct application to Hitec service):
Manual and Automatic testing procedures, Transmitter Pulse width measurement, Receiver Voltage measurement,
Direction of Rotation, Speed of Rotation, Fail Safe On-Off, End Point, Neutral Point, Fail Safe Point Preset
Servo Test & Programmable functions of New HFP-20 :
Basically Same as old HFP-10, and "Overload protection Setting" and "Servo Resolution mode Setting" Function added.

Programmer........Function...................Conve ntional........HS-50xx..........HS-7xxx
.................................................. ..........HS-5/6xxx.........Digital Micro.....Digital
.................................................. ..........Digital Servos......Servos...........Servos
HFP-10 & 20........Servo Test..............................Yes..........Yes .................Yes
.........................RX Pulse & Voltage Measure.......Yes..........Yes.................Yes
.........................Reset.................... .................Yes..........Yes................. Yes
.........................Dead Band Setting...................Yes..........Yes........ .........Yes
.........................Servo Speed...........................Yes..........Yes.. ...............Yes
.........................Change Rotation (CW/CCW).......Yes..........Yes.................Yes
.........................Fail Safe On/Off.......................Yes...........Yes....... .........Yes
.........................EPA/Fail Safe Position...............Yes...........Yes.......... .......Yes
......... HFP-20
........................Overload Protection...................No.............Yes... ...........Yes
........................Resolution Mode Setting.............No..............No............ ...Yes

G2 The Second Generation Premium Digital Servos (HS-7XXX series)
*Overload protection : This function is to protect the servo(HS-50XX servos & HS-7XXX servos) from the overload condition. Once the servo is forced with overload condition for certain time, the motor output will be decreased to the setting level set by user. Please note that this function is deactivated (off) in factory setting.(factory default : overload protection off)
*Resolution mode setting : There are two resolution modes(High and Normal) in HS-7XXX servos. Factory default is set at "High" resolution, and servo travel will be 120 degree. If user needs to widen the servo travel, user may select normal resolution so that the servo travel can be widened to maximum of 180 degrees.
(Factory default : Resolution mode High)
"NOTE" : These new functions (Overload protection Setting & Resolution Mode Setting) can be programmed by new Hitec servo programmer, HFP-20 .
HPP-21
HPP-21 Plus
HPP-21 RCU discussion - new PC based Hitec Digital Servo Programmer to be released shortly.
HMI Digital Servo Programmer for Robotics servos,
• Compatible with the following DIGITAL servos:
HSR-8498, HSR-5990TG,HSR-5980SG,HSR 5498SG, Hitec Digital ROBOT Servo.
Regards
Alan T.
Alan's Hobby, Model & RC FAQ Web Links