Company: SONM
Filing Date: 2025-06-25
Form Type: DEFA14A
Source: 0001641172-25-016376
Chunk: 0

Company: SONIM TECHNOLOGIES INC
Filing Date: 2025-06-25
Form: DEFA14A
Chunk 0
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<div align='center'>UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a) of the

Securities Exchange Act of 1934</div>

Filed by the Registrant ☒

Filed by a Party other than the Registrant ☐

Check the appropriate box:

| ☐ | Preliminary                                                       
 Proxy Statement                                                   |
| ☐ | Confidential,                                                     
 for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) |
| ☐ | Definitive                                                        
 Proxy Statement                                                   |
| ☒ | Definitive                                                        
 Additional Materials                                              |
| ☐ | Soliciting                                                        
 Material under §240.14a-12                                        |

<div align='center'>Sonim Technologies, Inc.

(Name of Registrant as Specified In Its Charter)

(Name of Person(s) Filing Proxy Statement, if other than the Registrant)</div>

Payment of Filing Fee (Check all boxes that apply):

| ☒ | No           
 fee required |

| ☐ | Fee                                        
 paid previously with preliminary materials |

| ☐ | Fee                                                                                             
 computed on table in exhibit required by Item 25(b) per Exchange Act Rules 14a-6(i)(1) and 0-11 |

<div align='center'>UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 OR 15(d)

of The Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): June 25, 2025

Sonim Technologies, Inc.

(Exact name of registrant as specified in its charter)</div>

| Delaware              |     | 001-38907   |     | 94-3336783     |
| (State                
 or other jurisdiction 
 of                    
 incorporation)        |     | -Commission 
 File        
 Number      |     | -IRS           
 Employer       
 Identification 
 No.            |

<div align='center'>4445 Eastgate Mall, Suite 200,

San Diego, CA 92121

(Address of principal executive offices, including Zip Code)

(650) 378-8100

(Registrant’s telephone number, including area code)

Not applicable.

(Former name or former address, if changed since last report.)</div>

Check the appropriate box below