Compute Capability of GTX 970 and cudnn

My System:

OS: Ubuntu 18.04
GPU: GTX 970
CUDA: 9.0
cuDNN: 7

I’ve installed CUDA/cuDNN and when i run ./mnistCUDNN I got these results:

cudnnGetVersion() : 7301 , CUDNN_VERSION from cudnn.h : 7301 (7.3.1)
Host compiler version : GCC 6.4.0
There are 1 CUDA capable devices on your machine :
device 0 : sms  4  Capabilities 2.1, SmClock 1800.0 Mhz, MemSize (Mb) 4536, MemClock 2050.0 Mhz, Ecc=0, boardGroupID=0
Using device 0

Testing single precision
CUDNN failure
Error: CUDNN_STATUS_ARCH_MISMATCH
mnistCUDNN.cpp:394
Aborting...

I found in this link https://blog.pattapongj.com/install-tensorflow-with-gpu-cuda-support-on-ubuntu-16-04-42c90592855b that the minimum supported CUDA architecture is 3.0. However, I found in wikipedia that GC GTX 970 has Maxwell architecture with compute capability of 5.2.

Has anyone an explanation about that?

These are the results of ./nvidia-smi

+-----------------------------------------------------------------------------+
| NVIDIA-SMI 390.87                 Driver Version: 390.87                    |
|-------------------------------+----------------------+----------------------+
| GPU  Name        Persistence-M| Bus-Id        Disp.A | Volatile Uncorr. ECC |
| Fan  Temp  Perf  Pwr:Usage/Cap|         Memory-Usage | GPU-Util  Compute M. |
|===============================+======================+======================|
|   0  GeForce GTX 970     Off  | 00000000:0F:00.0 N/A |                  N/A |
| 40%   39C   P12    N/A /  N/A |    217MiB /  4536MiB |     N/A      Default |
+-------------------------------+----------------------+----------------------+
                                                                               
+-----------------------------------------------------------------------------+
| Processes:                                                       GPU Memory |
|  GPU       PID   Type   Process name                             Usage      |
|=============================================================================|
|    0                    Not Supported                                       |
+-----------------------------------------------------------------------------+

Thank you very much.