SEC Form 4

FORM 4		UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response: 0.5
	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person* Chen Weidong (Last) (First) (Middle) C/O CASA SYSTEMS, INC. 100 OLD RIVER ROAD (Street) ANDOVER MA 01810 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol Casa Systems Inc [ CASA ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) Director 10% Owner X Officer (give title below) Other (specify below) Chief Technology Officer
	3. Date of Earliest Transaction (Month/Day/Year) 02/23/2021
	4. If Amendment, Date of Original Filed (Month/Day/Year) 02/25/2021	6. Individual or Joint/Group Filing (Check Applicable Line) X Form filed by One Reporting Person Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Restricted Stock Units(1)	(2)	02/23/2021		A		119,834		(3)(4)	(3)(4)	Common Stock	119,834	$0.00	119,834	D

Explanation of Responses:

1. The original Form 4, filed February 25, 2021, is being amended by this Form 4 amendment solely to correct an administrative error related to the disclosure of the vesting schedule for 23,967 of the shares underlying this award. Due to an administrative error, those shares were reported as being subject to time-based vesting criteria instead of performance-based vesting criteria.

2. Each Restricted Stock Unit ("RSU") represents the right to receive one share of common stock, $0.001 par value per share (the "Common Stock") of Casa Systems, Inc. (the "Company") upon vesting, subject to the reporting person's continued service relationship with the Company and the other terms and conditions set forth in the applicable RSU agreement. In the sole discretion of the Company's board of directors, the Company may, with respect to any applicable vesting date, deliver to the reporting person Common Stock or cash having a fair market value equal to the number of shares of Common Stock underlying the portion of the RSU that vested on such date, payable within 30 days of the vesting date, less applicable taxes.

3. The award consists of two separate issuances of RSUs. The first issuance of 95,867 RSUs are subject to time-based vesting and are scheduled to vest over four years, with 25% of the shares underlying the award vesting on January 1, 2022, and 25% of the shares underlying the award vesting at the end of each successive one-year period thereafter. The second issuance of 23,967 RSUs are subject to performance-based vesting, the conditions for which are met upon the Company's level of achievement of pre-established performance parameters, as approved by the Company's Board of Directors, related to either or both of (i) the Company's relative Total Shareholder Return ("TSR") performance against the TSR of the companies listed in the Russell 2000 Index, and (ii) the absolute stock price performance of the Company's common stock, in each case,

4. (continued from footnote 3) measured over the three-year period beginning on January 1, 2021 and ending on January 1, 2024, and subject to the other terms and conditions set forth in the applicable RSU agreement. These RSUs have no expiration date.

Remarks:

	/s/ Timothy Rodenberger, as Attorney-in-Fact	05/05/2021
	** Signature of Reporting Person	Date
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